Just a thought...
When Luffy woke up, it seemed like just another day. The morning started off with a Marine ship firing off cannons at them (which always missed, of course) and the guys beating the crap out of the Marines who had attempted to board the Sunny. Nami and Robin sunbathed the entire time they were fighting, Robin occassionally glancing up to snap a couple necks or two whenever she felt like it. Nami threw her hot tea at a Marine who had wandered too close and blocked the sunlight, causing him to scream and stumble backwards, ultimately falling overboard.
Amidst the battle, Luffy punched Marines left and right, his fighting companions just multicolored blurs zipping left and right, blowing Marines into the water. Luffy caught sight of Zoro slicing a Marine, Franky and Usopp's combined arsenal blowing up at least two dozen, Sanji viciously kicking several at once, Chopper goring another two with his antlers in Horn Point, and Brook seemingly flying through the crowds, Marines jetting left and right from his path of destruction.
Then everything went wrong when suddenly, Luffy found himself alone.
Everyone had vanished.
The Marines were gone, the boys were gone, even Nami and Robin had disappeared from their spot on the deck. Luffy blinked once, then twice.
"Where'd everyone go?" Luffy asked out loud. After the initial shock had worn off, Luffy began to panic. He ran across the ship back and forth, as if hoping they would reappear again. After five minutes, it was clear they were... gone.
"HEEEY!!" Luffy shouted to the sky. "WHAT'S GOING ON?!?" He flopped down on the grass. Maybe it was just a dream. Maybe he had been knocked out or something, or there was a Marine with a Mystery Devil Fruit, or maybe he had just passed out from hunger since there wasn't time for Sanji to cook breakfast for them.
Luffy shielded his eyes as the sunlight seemed to intensify. He squinted against the white light, which was enveloping his vision and burning into his head he couldn't see no he couldn't wake up wake up wake up-
Luffy sat upright. The light was gone. No. Everything was gone. He was sitting in what appeared to be some sort of metal bed with a glass door. It smelled like Chopper's infirmary. It appeared to be in some sort of large antechamber, with more mysterious metal bed-pods all around him, some even hung up on the walls. There were thick cables running from the pods to a giant metal thing in the center of the room which gave off crackly noises that hurt Luffy's ears.
Someone cleared their throat behind Luffy.
Luffy whipped around, tense. He immediately relaxed when he saw who it was. "Oh! Robin! What's going on? What's up with all the metal pea-pod things here? Where's everyone else? Why are you-"
"Lu- Luffy." Robin said. "This might be a bit hard for you to understand... can you tell me what's the date today?"
"I dunno. We don't keep track, remember? It's the Age of the Pirates."
"No. It's the year 2325. Third decade of the twenty fourth century." Robin said. Luffy finally noticed she was wearing a long white coat, similar to what Chopper would wear whenever he was bandaging Luffy up in Heavy Point.
"When's that?" Luffy asked, tilting his head.
"You're not going to get far telling him like that." another figure walked up to them. His face was hidden by a blank metal mask that covered his entire face, even his eyes and mouth.
"Who're you? Robin, what's going on?" Luffy turned to Robin.
"Look. Luke." The man leaned on the pod Luffy was sitting in. "Everything was a dream. A lie. Virtual reality. Fake memories. Capiche?"
"What're you talking about, weird guy?" Luffy asked, scrunching his brow. "And my name is Luffy. Monkey D. Luffy."
"That's not your name." the man sounded like he was gritting his teeth. "Alright. Tell me who you spent Christmas with when you were eight years old."
"My dad." Luffy responded automatically. His mouth gaped in confusion from his answer. "But my dad... he's not..."
"Good. His memories are resurfacing." the man stood up.
"It's not a good idea to bring him to reality so suddenly. It could break his mind." Robin said softly.
"We don't have time!" the man hissed, grabbing Robin's shoulders and shaking her lightly. "The rioters are probably going to start hacking at another cable any minute now!"
"Hey! Don't talk to her like that!" Luffy tried to pull himself up but found there were small wires around his ankles, binding him down to the pod. "Robin, what the hell is going on?!"
"Luffy, calm down. Please." Robin gently pushed down on the boy's shoulder. "We'll explain everything later."
"I told you, we don't have time!" the man said loudly. "Zack's division is having trouble with the crowd and Sandy was already sent to the infirmary!"
"Is the mob armed?"
"SOMEONE TELL ME WHAT'S GOING ON!!" Luffy yelled.
Robin knelt down beside Luffy and looked at him sadly. Luffy stared at her eyes. They were green.
"What... what you lived- no, what you imagined to be your life was nothing but a virtual simulation part of our company's research on the effects of fantasy-influenced situations on the human mind. In simple terms, of course."
Luffy continued to stare at her blankly.
"Remember, he was an idiot in that world." the man muttered to Robin.
Robin took a deep breath. "Luffy, everything was just a... dream. None of it was real. Your real name is Luke Marco. Your father volunteered you to be part of our experiment."
"None of it was real." Luffy repeated dully.
"Don't call me that."
"Luffy... try to remember your real life."
Luffy closed his eyes and clamped his hands over his ears. Suddenly, unfamiliar images that felt strangely nostalgic came rushing into his head. A woman waving a rattle above his face. A man holding him as he rode a bike. A boy throwing a football to him. A young girl offering him a chocolate bar. A little brown dog running down a sandy beach. A classroom filled with students. A house in a suburb. A family. He was in it, wasn't he?
"None of it was real..." Luffy opened his eyes which widened with horror. "Why? But- Robin! You were on the... Sunny..."
"I was in your world to monitor your progress. Every one of our scientists is assigned to one of our subjects to keep track of them and to manipulate whatever they need to ensure a content virtual life. Haven't you noticed? In that world of pirates, no one died but for nameless Marines and bounty hunters. The Marines' cannon fire never hit the ship. No one ever got sick, except for Nami, and that was merely to lead up to the events in which you met Chopper."
Luffy's jaw continued to hang slack.
"Crocodile was a faulty program. He nearly killed you when he wasn't supposed to. That was where I came in. Remember? I saved you twice. No, three times, if you count the end of your battle with Lucci. That was another glitch in the program. I played out my role correctly and blended in with that world as to keep any suspicions down low. You never noticed. That was why I was so impossibly knowledgable of nearly everything you had to ask. I helped program that world. I knew everything." Robin said.
Luffy curled his knees up to his chest and stared at the wires around his ankles.
"As to why you were suddenly taken away from that world of pirates and adventure? Well-"
"I'll explain." the man in the mask interuppted Robin. "There's a bunch of people who think what we're doing is inhumane and cruel. Bullshit." the man probably would have spat on the ground had it not been for the mask. "They infiltrated our headquarters and tried to break the wires and connections bridging our subjects to their individual worlds. They had managed to cut just one link. Yours."
"There's other people?" Luffy looked up in disbelief, ignoring the last bit. The man stood back and spread his arms, indicating all the other pods.
"That boy thinks he's a ninja. That boy is in a world where he is a spirit-guider who fights off evil. That other boy believes he lives in a world inhabited by super-powered creatures that can be contained in small capsules. The girl over there thinks she's the reincarnation of a space warrior, and that group of boys think they are among the last wolves in a war-ridden world. Oh, that that girl lives in a reality that almost seems real, but there's supernatural occurences going on in there. There's countless others. And they all have one thing in common- they are happy. As you were. You were happy, weren't you, Luke?"
Just then, another man rushed in out of nowhere. "Professors, we captured all the rioters and repaired Luke Marco's virtual reality link. It's good to go."
"Good, good." the masked man placed a hand on Luffy's chest and pushed him back down into the pod. The glass door was shut over him.
"Wait! Wait!" Luffy yelled, his voice muffled. Robin looked down at him through the tinted glass sadly. She smiled.
There was a bright flash of light that burned into Luffy's head everything was burning he couldn't see no couldn't too bright no wake up wake up wake up-
"MEAT!" Luffy answered, sitting upright. Chopper was standing beside his bed, wringing his hooves worridly. "Oh, Chopper! Did Sanji cook lunch yet? I'm starving."
"Everyone! Luffy woke up!" Chopper ignored Luffy, screaming out the door. The infirmary was suddenly swamped by the Strawhats.
"Yohohoho! We all thought you had sustained a serious injury there, Luffy-san!" Brook laughed.
"Don't worry us like that, Strawhat-bro!" Franky punched Luffy's shoulder lightly, wiping away tears.
"What happened?" Luffy rubbed his slightly sore head.
"You fell overboard." Zoro muttered, looking down at the ground. "I couldn't get there in time. You were half-drowned by the time I got you up. Sorry, Luffy."
"Jeez, marimo. You're too hard on yourself. That's probably why your head is as thick as a coconut." Sanji smirked.
"WHAT WAS THAT?!?"
"Stop it, both of you!" Nami held them back from strangling each other. "Luffy, you really should be more careful when you're jumping back and forth between ships like that!"
"W-well, I wasn't worried at all!" Usopp sniffled, thumping his chest. He patted Luffy on the back. "We'll have a feast tonight to celebrate!"
"Oi, I'm not so sure if we have enough supplies." Sanji said.
"We'll reach another island in a couple days, so we'll be fine." Nami said.
"ANYTHING FOR NAMI-SWAAAAN~!" Sanji shouted.
"Oi, Chopper, do I have to stay here all day?" Luffy asked.
"No... I guess you'll be alright. It isn't the first time you nearly drowned, anyways." Chopper giggled.
"Yosh! Usopp, Chopper, let's go fishing!" Luffy jumped out of the bed and ran out the door, Usopp and Chopper sprinting after him, yelling at him to slow down.
"Che." Sanji shook his head and left the infirmary. Franky, Brook, Nami, and Zoro followed.
Robin stood alone in the small room. She looked out the door with a trace of sadness on her face. Luffy poked his head back inside.
"Oi, Robin, you comin'?" Luffy asked.
"Yes... Captain-san. I'm coming." Robin said softly, her blue eyes appearing wet for a split second. She blinked and followed Luffy outside.