This started out as a piece of fluff, because building sandcastles is cool and flying buttresses are funny. But it turned into something else. That's just the way it goes.

Some days just don't turn out the way you want them; other days are a gift you never expect.

Wilkins Lake, located in northern Virginia, was not a large lake, but it was perfect for John Winchester's needs. John needed a relatively self-contained, yet open place for the boys to blow off some steam; they had been confined to a cracked and broken strip of asphalt parading as a "playground" for three days while he did some heavy duty research. John needed a place where Dean could watch Sammy, and John could keep half an eye on them both. But what John really needed was a place to spend the day that didn't involve polyester carpeting, unidentifiable smells or crappy air-conditioning. That would be where they spent the night, but not where they spent the day.

John tried to ignore Sammy's dance of impatience while he set himself up at a picnic table not far from the water's edge. Dean, at thirteen, was too disciplined to show any signs of glee over spending the day at a lake; but Sammy, at nine, did not display the same self-control.

"All right, boys." John said as he straightened up. "Here are the rules: Stay within ten feet on either side of the lifeguard's chair." Both boys nodded, they knew that was coming. "Sammy, no swimming out past where you can stand. You mind Dean if he tells you to come in." John waited to see if Sam's small grimace would blossom into a full blown complaint, but Sam exhibited enough restraint to keep his mouth shut. John nodded with satisfaction.

"We don't usually get a day to spend like this, boys, but I'm telling you now…." John looked sternly at each boy in turn as his voice took on a warning tone. "If I catch even a hint of the nonsense that's been going on the past few days, we are packing up and going right back to that motel, and the two of you can spend the day running sprints in that 'playground'." Sam's eyes grew wide at the thought of losing the day at the lake; Dean flushed slightly, knowing that most of the "nonsense" could be attributed to him, but he didn't drop his gaze from his father's. A day like this was too precious to screw up over baiting Sammy – there would be no "nonsense" today.

After John took the measure of each boy and was satisfied, he dismissed them. "The lake's waiting," he said with a ghost of a smile. Sammy whooped, did a one-eighty, stripped off his t-shirt and headed right for the water. Dean paused as John gave one last direction. "Dean…you're on duty."

Dean acknowledged the order with a nod and a "yes, sir" before following Sam down to the lake's edge. Dean called Sam back in almost immediately, insisting on applying liberal amounts of sunscreen to Sam's shoulders and back, while ordering Sam to take care of his own face and chest. Sam hastily helped apply the lotion to Dean's back and then flung himself back into the water. Dean quickly followed, and a game of tag ensued.

John turned his attention to the papers spread out before him.

John kept half an ear on the boys throughout the morning. Dean kept Sam entertained playing games that often resembled training exercises – contests involving holding their breath underwater, diving for rocks, and long distance swimming were the order of the morning. At one point, Sammy got involved with a group of boys around his own age that needed a fourth player in some convoluted game of Marco Polo; Dean was content to sit on the sand and watch.

It was something about Dean that always fascinated John; he just didn't like the water. On a rare day spent at a lake or pool, Sam would get the impression that Dean didn't want to play with him, but John knew that wasn't it. Both of the boys could swim and perform a rescue in the water – John had made sure of that. But Dean simply didn't delight in the water the way Sammy did. Sam could and did swim for hours; John thought that somewhere in their family history there must've been a selkie or mermaid in the mix, the way Sam took to the water. Dean was much more earth-bound. On a hot day like this, he'd go in the water and get wet and, if no one else was around, he'd play with Sammy; but once Sam connected with a group of kids – and Sam usually did – Dean preferred to spend his time on the shore.

Around noon, John called both of the boys in for lunch. The kids that Sam had been playing with scattered as well – some back to their families for lunch, some heading home. Sam and Dean chatted animatedly – Dean gave John a rundown of the results of the contests he and Sam had, and gave Sammy full credit for the ones he'd actually won. Sam talked about the boys he'd been playing with and attempted to explain the revised rules for Marco Polo. John smiled and relaxed listening to them both, knowing that spending the day at the lake had already been totally worth fighting with the sun glare and the gusts of wind that tried to steal his papers.

After eating, John sent the boys back to the lake. They didn't need to be told, but he told them anyway: "No swimming for an hour, boys. Keep yourselves amused until then." Dean's watch beeped as he set the timer and Sammy tried to hide his disappointment about being banned from the water. John caught Dean's eye and gave a nod. You're still on duty. It didn't have to be said; it was understood.

Dean took off, walking clockwise around the lake with Sammy trailing behind him. John could hear Sammy's chatter fade in volume as the boys got further away, and he turned his attention back to his work. The walk around the lake didn't take too long, and the boys ended up on the shore near the picnic table with more than half an hour left to kill. John listened to them in the background, but continued working. He could hear Sam sigh and imagined his youngest was staring longingly at the water. He heard Dean quickly intervene.

"C'mon, Sammy. Let's make a sandcastle."

Sam was somewhat startled at the suggestion. So was John. Dean had recently been feeling the pride of all of his thirteen years, and sandcastles were definitely not on his list of "cool" activities. But John understood Dean and, in this circumstance, Dean would do anything to prevent the whining that would get them confined to the "playground" at the motel. Sam eagerly agreed to the project, and began digging along the area Dean had sketched out. John turned his full attention back to his work.

About half an hour later, John called it quits on the research he'd been doing. He'd left some books he didn't realize he'd need back at the motel, and he'd done all he could with the materials he'd brought with him. John was satisfied with the work that he'd accomplished and, since he'd finally figured out the pattern of the demon they were tracking, he knew he had two more nights to prepare before the hunt. Getting back to the motel was on his mind, but not urgent. He was about to call the boys in and pack them all back to the motel, when he took a good look at what they had accomplished in the short time they'd been working.

Dean had sketched the castle's boundaries in the moist sand near the lake's shore. Both of the boys had started digging. All of the sand from the exterior had been tossed into the center of what would become the castle itself. Leaving Sammy to dig, Dean had scavenged the nearby area for tools – no brightly colored plastic, store-bought shovels and pails for the Winchesters – but Dean had made do with sticks, discarded cups and other materials.

The center of the castle had begun to take shape; the mound of dirt had taken on the appearance of a building. John didn't know how Dean managed it, but it looked to him like the perimeter of the castle yard and the sides of the main building were squared off. That was Dean for you; the boy could just see things and make them work – he was a regular MacGyver.

As John was watching, Sam took a step back to observe the result of their efforts. His back was to John, but John could imagine the speculative look on the face of his younger son. "We need ramparts." Sam declared.

Dean looked up from where he was embedding half of a cup into the wall to create an archway. "What?"

"We need ramparts." Sam repeated, as if it explained everything. He waved his arm in the direction of the castle.

Dean stood and walked over to where Sam was standing. He took up a position next to his brother so his view would be the same. "What's a rampart?" With Dean's back to the picnic table, John couldn't see his expression, but he could hear the confusion in his voice. He could also see Dean's shoulders tense, and knew it took a lot for his eldest to admit he didn't know what Sam was talking about. John knew that, if there'd been other boys around, Dean never would have asked.

Sam, who knew his brother better than anyone, knew better than trying to explain with just words. Picking up a stick from the sand, Sam sketched a quick drawing. "It's like this," Sam knelt on the sand and explained while pointing with the stick, "The main castle or fort sits in the middle. The ramparts are the protective walls around the outside. It's where the soldiers would stand to shoot arrows and pour boiling oil on the invaders." Sammy's tone was a little too enthusiastic about the boiling oil.

John could see the set of Dean's shoulders relax as he listened to Sam. Dean had moved to stand behind Sam where he could peer over Sam's shoulder, so John could see the concentration on his face in profile. Then Dean stepped away from Sam and walked around the perimeter of the castle they'd been building. He gazed at what they'd made, but his face had a distant look; he was clearly seeing something more, something John and Sam couldn't see.

"So what we need to do," Dean said, still with that faraway look on his face, "is to build up the area around the fort, and make the walls to house the defenders. Okay…." Dean sort of came back to himself and looked at Sam. "Okay, Sammy. We can do that. But we'll need some more materials."

John knew in the instant the "castle" became a "fort" that the project had become Dean's and not Sam's. If Sam noticed a difference, he clearly didn't care; either way he got to spend the day digging in the sand and making something with his big brother. It was then that John decided they would stay at the lake for a little while longer.

There's something about boys digging and building in the sand that attracts other boys. Before long, two of the boys who had played Marco Polo with Sam earlier wandered over to watch. Dean didn't even hesitate before putting them to work. He set one of the boys to collecting twigs and sticks, and added the other boy to Sammy's digging detail. Dean himself continued working on the fort.

John watched his boys, completely fascinated. All of the observational tricks he'd learned while hunting came into play, and he watched his boys, learning things he never knew or simply missed. It was rare for John to see Dean in a group of children. They weren't a family that had time for organized sports or play dates. John usually saw Dean with Sam, and that was it. Sammy followed Dean around and followed his lead because that's what younger brothers do. So John didn't realize that, in a group, Dean was a natural leader.

Dean was older than the boys who'd come over to join them, but his age didn't make him the leader by default. He was organized and clearly had a vision. He gave everyone a job they could be successful at, and at the same time made it clear that every job was important. Dean didn't lord his position over the other boys; they instinctively knew that he'd do any job he assigned them. It made them more willing to work. Dean had the control of a drill sergeant without ever raising his voice. It was astonishing.

Whereas Dean held himself slightly apart and tended to work alone even in the group, Sammy was a totally social animal – able to work one-on-one with Dean, and just as able to quickly switch gears and work with a new partner. He chatted easily with the boys he'd played with in the morning, and effortlessly brought in two new boys as they came along. Sam's highly developed verbal skills definitely came into play as the group expanded. Dean would make assignments, but it was Sam who took the time to explain them. If Dean was the General, Sam was definitely his first Lieutenant.

The afternoon waned, but the sun was bright in the sky as the group continued to work. The fort had been completed, and Dean supervised the construction of the ramparts. Without any acknowledgement other than a brief moment of eye contact and a nod of the head, Dean knew that John was watching and that he was no longer "on duty." This gave Dean the freedom to range a little further looking for materials, knowing Sam was under John's watchful eye.

Sammy was firmly embedded in moat construction and wasn't going anywhere. His constant chatter gave John all the feedback he needed to know that Sammy was fine. So instead of keeping an eye on Sam, John kept an eye on Dean. John watched as Dean took his t-shirt down to the water's edge, tossed it in the lake, and pulled it over his head before heading further away to scavenge supplies. It was then that John noticed how snugly the shirt fit on Dean. That observation led to the realization that his cut-off jean shorts were also a tight fit.

John propped his chin in his hand and took a really good look at Dean; what he saw brought a lump to his throat, because he somehow had missed his boy turning into a man. The thinking was overdramatic, of course, but it briefly crossed his mind that Mary would kill him for not noticing the growth spurt his son had obviously just completed. A quick glance at Sammy and the other younger boys confirmed what John was seeing – Dean simply wasn't built like them anymore. Where the younger boys were rounder with the last remnants of baby fat, Dean was broader through the shoulders and thinner through the waist. His long limbs hinted at the height he would probably achieve when he was fully grown.

John was astonished and amazed, painfully aware of this rare glimpse he was getting of his son. Dean moved with extraordinary grace. He had an awareness of his space that very few people had, let alone a boy making a hard left into puberty. He had none of that gangly, awkwardness so typical of boys at that age. It made John's heart swell with pride when he realized what it was that set Dean apart – he moved like a soldier. And in the very deepest, darkest corner of his mind, John recognized that seeing it broke his heart a little, too.

Dean returned quickly from his mission carrying handfuls of bark, sticks, leaves and rocks. The younger boys ogled his finds appreciatively. Dean dumped his loot before the fourth, unfinished wall. This was the wall that would house the main gate with the bridge to cross the moat. John had heard some speculation from the Marco Polo boys that building a wall with a door would be impossible; Sam flatly declared that Dean would figure it out. Sam's confidence in his older brother made John smile.

As Dean stood before the last wall, Sam moved to stand next to him. Both appeared pleased with the work that had been done. "You know what would be cool?" Sammy ventured. Dean responded with a raised eyebrow. "Flying buttresses!" Sam continued.

Sam's declaration got a quick response from the other boys. "Flying what?" one boy with shockingly red hair squeaked as he blushed from his neck to his very red hairline.

"Butt dresses." a smaller boy answered, as he stuck out his rear and wiggled it around.

Sam, using his tactic from earlier, tried to explain by drawing in the sand, but his eloquence was wasted; after all, his audience was a group of mostly nine year old boys. "Flying butt dresses!" a dark-haired boy yelled, and promptly fell over laughing. The conversation quickly disintegrated into accusations of "you're a flying butt dress" and "your mom wears flying butt dresses." Things might have calmed down after the initial hysteria, but then one of the boys shrieked something about "butt monkeys" and it was all over. The area around the fort was surrounded by shrieking, laughing boys. Some had fallen to the ground; others had their hands propped on their knees trying to remain upright. Even Dean had been swept up in the laughter, but he was laughing more at Sam's repeated attempts to explain a flying buttress and the totally befuddled look on his brother's face. John was hard-pressed to hide his own chuckles.

Then, disaster struck. One of the Marco Polo boys, inebriated by laughter, attempted to stagger over toward the front of the fort but tripped on the dark haired boy who'd never pulled himself up off the sand. He stumbled into the moat and, losing his footing, fell forward with his hands outstretched toward the fort. A collective gasp went up from the assembled boys who could only watch with frozen horror. John half-rose from his seat knowing he could never prevent the fall that was about to happen; he was just too far away.

But Dean wasn't. With his right foot firmly planted in the fort's courtyard, Dean reached out for the falling boy's arm. Grabbing the boy's wrist with his left hand, Dean used his right hand to support the boy's weight as he used the boy's forward momentum to lift him over and across the empty wall. The movement spun Dean around but, when he released the boy, his own momentum shifted backward and he lost his footing in the loose sand. John could read the despair on Dean's face because Dean knew he was going to fall right onto the fort. And he would have, if Sammy hadn't jumped into the moat and reached out in time to steady him.

A release of the breath that everyone had been holding sighed over the unnaturally quiet lakeside. One boy dared a reverent, "Whoa."

Dean and Sam shared a glance. Then Sammy grinned. Dean grinned back. John resumed his seat.

Clearing his throat John got the boy's attention. Two pairs of hazel eyes snapped his way. "Fifteen minutes, boys."

"Yes, sir." The answers came quickly enough, but Sam wasn't able to hide the disappointment on his face. Dean didn't let him dwell – there was still one last wall to build.

Exactly fifteen minutes later, John Winchester stood before the completed fort – fourth wall and bridge intact. All of the boys who had helped build it were arranged around the perimeter. Sam and Dean were standing on either side. John nodded solemnly. "It's a damn good fort, boys." The younger boys were impressed with the inclusion of a curse word to describe the appreciation of all their hard work. Sammy reached up and squeezed John's hand. Dean nodded like a shadow of his father, but the pride in his voice was evident. "Yeah, it's pretty good, sir."

As they walked back to the car, Sam turned around repeatedly as though trying to reassure himself the fort wasn't going to disintegrate as soon as they turned away. Dean had already taken a good long look when they were standing before it; then he never looked back.

When they returned to the motel, John found himself in an unusually good mood, and he still wasn't ready to be confined to the room. "All right boys," he announced, "get yourselves cleaned up and ready to go in half an hour. We're going to find someplace to eat."

Stunned twin gazes met his own, and then the boys sprang into action. Dean sent Sam into the bathroom first and collected Sam's discarded clothing into a pile. He dug through their shared duffel to find Sam something clean to wear – or at least something clean enough to wear in public. Once Sam emerged from the bathroom, Dean ducked inside, taking his change of clothing with him. Sam got dressed in a flash, and then propped himself up against the headboard of the bed he shared with Dean to read a book he'd picked up.

John didn't approve of the boys getting attached to "stuff;" when they were traveling, they had to keep unnecessary items down to a minimum. But Sam had a knack of knowing which motel clerks he could approach about books that might have been left behind by previous guests. So John and Sam had made a deal: Sam could hang onto any book that John considered appropriate as long as they were staying but, when they left, Sam would have to leave the books behind – finished or unfinished. Sam had hit the mother lode when they'd pulled into this motel – three Hardy Boy books he hadn't read before. He'd finished the first one, was deep into the second one and was already looking forward to reading the third. Dean emerged from the bathroom at about the same time Sam put down his book with great satisfaction. John checked his watch – it had been twenty-eight minutes. He nodded with approval. "Let's go."

It seemed to John that the quality of the diners increased in direct proportion to the distance they traveled from the crappy motel of the day, so he drove for a solid twenty minutes before finding a diner that looked good. The meal itself was unremarkable, but the company was entertaining. Sam chatted animatedly about the book he'd just finished reading – in his opinion, he and Dean would never have fallen for the obvious trap the Hardys had walked into. With some prompting, Dean explained the architecture behind the ramparts and bridge. And both boys rehashed the building experience from start to finish. This of course included a rehash of the "flying buttress" conversation, which sent both boys into fits of smothered giggles because John didn't approve of hysteria at the dinner table, particularly in public. Once the boys had brought themselves back under control, John signaled for the indulgent waitress to bring them the dessert menu. It was a rare night indeed.

John should have realized something was wrong when Dean stopped talking, but it was very easy to let Sammy's chatter fill all the space between them. John should have noticed how stiffly Dean held himself both at the diner and in the car on the ride back to the motel. John should have picked up on how Dean wouldn't look him in the eye, but he missed all the signs. He might have missed it all together if not for Sammy's breathless, "Oh Dean…."

John looked up from the desk where he was organizing his papers, to the bathroom where Dean had tried to slip past Sammy. Dean tried to close the door, but Sam stood frozen in the doorway, amazed at the brilliant sunburn on Dean's back and shoulders.

Dean's eyes met John's for the barest of moments before he looked away, ashamed. "It's not so bad, Sammy."

John swallowed hard, and looked away as well. He was beset by a myriad of emotions. John wanted to gather his boy in his arms and apologize profusely for not paying more attention. Dean had always been fair like Mary, so he'd peel and burn – not get brown like Sam and John. He wanted to shout at Dean for not taking care of himself: You know better than to be in the sun unprotected! But, in his mind, John replayed the moment when Dean threw his shirt in the lake, and a small voice in his head whispered that Dean had been trying to take care of himself. An even smaller voice that sounded like Mary's whispered, "But he shouldn't have to."

In the space of time it took for John to get control of himself, something happened. Sam took over. Without being asked, Sam was on duty.

Sam took Dean by the arm and led him back to the foot of their bed. Then he gave Dean a little push so he'd sit down. It was a measure of how much the sunburn had already taken out of Dean that he didn't protest. Dean sat wearily, staring down at the hands loosely clasped between his legs, pointedly not looking at John, but clearly waiting for some kind of response. It was hard to tell if the tension in his posture was because of the pain he was in or the dressing down he was anticipating.

Sam trotted to the bathroom and back, bringing a glass of water and a pair of aspirin.

"Here, Dean." Sammy said, as he shoved the aspirin under Dean's nose. "Take these."

Dean did look up at John then. The boys both knew they were not allowed to self-medicate. Sam stood by confidently with his hand outstretched until John gave a nod of approval. Dean didn't hesitate to take the aspirin and swallow them down. Sam took the glass back to the bathroom and returned with a small jar of cold cream from the first aid kit. Then he knelt on the bed behind Dean and started to apply the salve to his back and shoulders.

For the second time that day, John was hit with a realization about one of his sons but, this time, it was Sam he saw in a new light. What was clear to him now was that Sam was no longer a baby. Would a baby know how to give first aid? Would a baby be so gentle and careful of his big brother? John watched as Sam gently but methodically rubbed the balm on Dean's sunburn. Dean gradually relaxed under his touch as the aspirin and the cold cream took effect. He murmured, "Thanks, Sammy," when his brother was done.

Sam finished his ministrations and returned the jar to the bathroom. When he returned to the room, he looked speculatively at Dean. "You should probably sleep with a shirt on, so the stuff doesn't just rub off all over the sheets." Dean nodded and stood up.

For the first time since the scene started, John spoke up. "Dean." His eldest tensed as he turned, expecting the tongue lashing to begin. Instead he was startled when John tossed him one of his undershirts. "Try this instead. Your shirts are too small. They'll be too tight."

Dean's expression was one of relief as he wiggled into John's t-shirt. Sam helped him get the shirt down his back. Once he was settled, Dean turned back to John, not quite standing at attention, but close enough. He was still waiting for John to respond to the flaming sunburn on his back. So John did. "It'll feel better in the morning, kiddo."

Dean blinked. "Yes, sir." The expression on his face clearly read, that's it? But no way in hell was he going to complain.

Still not quite sure what had just happened, or what hadn't happened, Dean turned to Sam. But he wasn't in the bathroom doorway where Dean was expecting him to be, so Dean continued turning. Sam had already finished changing for bed and was climbing under the scratchy sheets.

"What're you doin', Sammy?" Dean asked confused. He checked his watch, and so did John. It was only a little after eight – much earlier than the boys usually went to bed.

"I'm just tired." Sam replied.

John could see the confusion and disbelief warring on Dean's face. Dean really, really wanted to believe Sam was ready for bed because that would mean he could crawl into bed, too. He would never admit it out loud, but it was clear to see that the sunburn was causing him a lot of pain, and it had just worn him out. John knew, too, that the pain would soon be followed by chills and a fever. But if Dean could fall asleep quickly, he would sleep through the worst of it. Somehow, Sammy knew it, too.

John tried to watch without watching to see how the situation would play out. He settled himself down at the desk and tried to look like he was working. John understood why Dean hesitated. On a night when John didn't have to go out hunting but stayed in to research, Dean was still on duty. Dean was supposed to make sure Sammy stayed out of John's way and got to bed at an acceptable hour. Once Sam was in bed, Dean was no longer "on duty." Dean's whole world was skewed because Sam had effectively put himself to bed.

Dean sat down on his side of the bed and looked at Sam. "Are you feeling okay?"

"I'm fine, Dean – just tired. Building sandcastles is hard work." Sammy replied.

"It was a fort." Dean replied automatically. He shifted trying to adjust the shirt on his burned shoulders. "Are you really going to sleep now? You don't want to stay up and read one of those books?"

That was the deal breaker, John knew. If Sammy wanted to stay up and read, Dean would have to remain awake with him. He would do it, too, and not complain.

"Nope." Sam answered easily as he rolled over to turn off the lamp between the beds. "I can read in the morning."

Dean still didn't look like he quite believed what was going on, but he finished getting himself ready for bed and soon settled down next to Sammy. Dean lay on his stomach and pulled the pillow up tight under his face. He turned his face to the left to talk with Sam.

"The ramparts were a good idea, Sammy."

Sam rolled onto his side so he was facing Dean. "I liked how you made the bridge. If we had more time, I bet you could've made it work going up and down."

"Mmmm…I could've made it work."

John listened as his boys talked. Very soon afterwards there was no more talking, just the sound of Dean's deep and steady breathing. But, John knew, Sam wasn't asleep. He stopped pretending to work and moved quietly from the desk to his bed. John sat on the edge of his bed looking at the boys. Sam rolled over to face him. John leaned in like he was telling a secret.

"Nice job, Sammy."

Sam's grin lit his side of the room. "He really fell for it, didn't he, Daddy?"

"Sure did, kiddo." John couldn't hide the pride in his voice. Sam grinned again. "You know…" John began speculatively, "you probably shouldn't sleep with Dean-o tonight. All those legs and elbows of yours…." Sam instantly looked worried – he was a notoriously messy sleeper.

"I guess you'll just have to come on over here with me." John grinned as Sam whispered "Okay, Daddy!" slipped out of his bed and flung himself across the small space between them. They were quickly situated, seated up against the headboard, with Sam tucked up under John's left arm. Somehow, the third Hardy Boys book had joined them, and John found himself reading softly about the adventures of Frank, Joe and Fenton Hardy.

Apparently, building sandcastles was more exhausting than Sam realized, because he was asleep in less than ten minutes. John stayed where he was, with Sam curled in his arms, and tipped his head back against the wall. A movement from the other bed alerted John to Dean. He didn't have to look to know that Dean had realized, even in his sleep, that Sam was no longer in the bed. "I've got him, kiddo." John called out from his position. "Sammy's with me. Go back to sleep." Dean immediately settled down.

It was John's turn to be on duty.

The End