Considering the last few weeks had been a mess of monsters, giants and stuff of legends that even he couldn't name, Jason was glad for a break. Leo, anxious to use his new solar-powered canons, complained that it was too quiet.

"I don't like this, man," he'd said to Jason. "I feel like a monster attack's gonna come out of nowhere any second now."

"Relax," Jason had replied, "Just enjoy the peace, would you?" He didn't admit that it did seem strange that nothing had gone wrong. Usually, they were lucky if they got two minutes to breathe. And now, when they were so close to completing their quest, the lull seemed odd. But he didn't want to complain. He got a little tired of being a demigod sometimes; it was nice to just be a regular kid for a few days. He wanted to practice his sword fighting and spend some time with Piper and he couldn't help but feel a little grateful for the break.

Today, the sun was shining on the Argo II as it sailed through the foam-capped, calm waters of the Mediterranean Ocean. Hazel and Piper were using the training rooms below decks so Jason took his sword down to his room to polish. His room was small but functional. Unlike Annabeth who had cluttered hers with books, or Percy whose room was a mess of clothes and discarded chocolate wrappers, Jason's was simple and clean. He hadn't hung up any posters on the white walls or added any personal touches. He still didn't feel like he knew himself enough to do that. After spending time at Camp Half-Blood, it was harder to feel truly Roman. It would take him a while to get used to his own skin. The only decoration in the room was a mirror that hung above the sink (Leo had cleverly installed one in each room so no one had to queue for the bathroom in the mornings to brush their teeth).

Jason blinked at his reflection. It blinked back, looking as unsure as Jason felt.

With a sigh, he flopped down to his bed, taking care with his sword, and began to polish it.

"Percy, Coach Hedge is going to kill us if he finds us!" Annabeth protested half-heartedly as her boyfriend, Percy Jackson, tugged on her hand and led her down to the stables.

"Coach Hedge isn't here," Percy reminded her.

For a split second, it reminded Annabeth of why they were really there. They were on a quest and they only had a few days before they lost their chance to defeat Gaia. But there was a voice inside her head saying Go on, the ship is making good progress and there's nothing else you should be doing. You deserve this. She shook her head free of the doubts, smiled, and allowed Percy to lead into the disused Pegasus stables.

Ahead of her, Percy grinned. He had barely had any time to spend alone with Annabeth in months. It seemed like as soon as they had come out of one war, they were pitched into another. And Tartarus hadn't exactly been the most romantic of locations for a cosy chat. He loved every second he spent with her – well, almost; they did have a habit of disagreeing – but one of his favourite memories was the time she had brought him down to the stables while they were on their way to Rome. Even now, when so much was at stake, the stables felt like an untouchable safe haven. He figured they could afford to take five minutes off to be alone.

The stables were huge and bathed in a blue light coming below them, from the ocean beneath the huge glass doors that made up most of the floor. Despite its size, the room had a way of feeling cosy. Percy grabbed a horse blanket which had been flung over a stall door and spread it on the floor like a picnic blanket. He leaned against the ship's wall behind him when he sat down; Annabeth leaned into him.

"Do you remember when I first came to Camp? How much you hated me?" Percy said, twirling a strand of her blonde hair around his finger.

"How could I possibly forget?"

Percy laughed. "But that year, you said to me you would always fight on my side because we were friends. I could never have imagined what we'd have to go through. The Titan War was one thing – but this? Who would have seen this coming? And we made it, Annabeth, we're still a team."

Annabeth lifted her head off his shoulder to look at him but he wasn't looking at her. He was staring straight ahead and his green eyes looked dark. Angry. She remembered this look from being down in Tartarus. She had hoped it was a side effect from being around so many monsters. She knew and loved the Percy that made her laugh and could crack a joke even at the hardest times. This Percy felt like someone else.

Before she could say anything, Percy spoke again. "I feel so mad, Annabeth. For almost six years now we've been handling the gods' problems. They're supposed to be the powerful ones. I get it, demigods are always their sidekicks. That's the way it's always been. But I am so tired." The anger left his eyes and all that was left was fatigue. He looked like he didn't want to fight any more. Like he wanted to give up. Rage was understandable. Defeat was undoable. Annabeth squeezed his hand but if he felt it, he didn't let it show. "I just want all this to be over."

"It will be," Annabeth reassured him. She was surprised at how firm she sounded despite the fact a part of her felt like their ordeal was never ending too. "We will defeat Gaia, Percy. We have to. Not for the gods but for us. For Camp Half-Blood. And for Camp Jupiter and New Rome too. We have to do what's right, you know that. Sometimes I want to just let the gods deal with their own problems…but they're family. And family doesn't give up on family." Annabeth felt a lump in her throat and she forced herself to swallow. She'd been betrayed by family before. She couldn't lose Percy too. She just couldn't.

When she looked at him again, she met his eyes. He looked apologetic. "Annabeth, I didn't mean – I mean, I know what we have to do. And I know that I'll always be on your side. Always. And you're right. This will all be over soon and we'll have a new life. Together."

"Oh, gods, I swear if you hog the bathroom in the mornings…" Annabeth laughed because she knew if she didn't, she'd cry.

Percy laughed with her and pulled her closer. She smelled like lemon shampoo and it took him back to two years ago before she'd really been his to hold like this. He forgot his anger at the gods. Right now, only she existed.

Percy was smiling in a way he hadn't done in a long time. He leaned down and kissed her. Annabeth felt like her bones were molten lead, weighing her down and rooting her in this moment forever.

Suddenly Percy's arms slipped away from her and she felt him pull away. Before she could figure out what was happening, he was pushing her away from him. The force knocked her off the blanket and she slid across the glass floor, stopping only when her shoulder hit the wooden door of a nearby stall.

"W-what in Hades?" Annabeth spluttered. Her shoulder stung and she felt anger bubble up from the pit of her stomach. "Percy!"

"Annabeth?" Percy asked incredulously. He stood up shakily, looking down at his hands and around the stables like he'd been dropped from the sky and had no memory of getting here.

"No, I'm freaking Helen of Troy!" Annabeth yelled, standing up and rubbing her shoulder. "What is going on, Percy? That was so not funny."

"I'm not Percy," Percy replied slowly as if forming the words were difficult. "I-it's me, Jason."

Annabeth stared at Percy like he'd grown a third arm. "What are you talking about? Making sense right about now would be really great."

Whatever Percy had been about to say was cut off by a crash-crash-thud from upstairs, followed by a loud yell.

"Is that…Jason?" Annabeth asked sceptically. It had sounded like him but Jason wasn't the yelling type.

"Oh, gods," Percy – or Jason – groaned. "No, no, this can't be happening!"

"What is going on?" Annabeth demanded, addressing no one in particular. She looked suspiciously around the room, as if expecting someone to jump out from the shadows yelling Tricked you!

The ground shook a little as footsteps thundered down the steps to the stable. "Annabeth?" Jason's voice yelled, sounding panicked.

A red-faced and confused looking Jason burst into the room, panting heavily from having sprinted down the stairs.

"Oh, gods," Percy repeated again, shifting uncomfortably, "This is so not good."

"Is that me?" the boy who Annabeth thought was Jason said looking bemused at Percy. "That's me! Why am I in Jason's body?"

"Oh, no," Annabeth moaned, burying her face in her hands, "I knew it. This was too good to last."

"So, wait, that's my body but – Percy?" Jason, the real Jason who spoke from Percy's body, asked.

"Yeah, it's me," Percy replied, looking down at his more muscular arms and the Jupiter SPQR tattoo on his skin, "How did I end up in Jason's body? And, dude, your accent is so weird."

"I have a weird accent?" Jason retorted, "You sound like a West Coast cabbie!"

"Watch it," Percy warned.

"Boys," Annabeth pleaded, stepping between them, "Accents are not the biggest issue right now."

"You're right," Percy replied and stepped closer to Annabeth. He tried to put his arm around her but she shifted away.

"Sorry, Percy," she said, "I know it's you…but it feels so weird."

Percy swallowed his disappointment but he understood. Suddenly, realisation dawned on him and he turned to face Jason. It was weird, like looking in a mirror where your reflection had a life of its own. But this time, he was mad at his reflection. "Were you – I mean – did you kiss Annabeth?"

Percy watched his own face turn a violent shade of red. "Well, no!" Jason protested, "I didn't ask for this! I wasn't doing anything with Annabeth and it's not my fault you were when I was zapped into your body!"

"That's my girlfriend!" Percy cried outraged. "Gods!"

"Percy, it wasn't his fault," Annabeth said. But she felt freaked out beyond belief. "We need to focus on why it happened – and who could have done something like this? Jason, what were you doing when this switch happened?"

Annabeth realised she'd turned to face Jason's body but corrected herself and faced Percy instead. Gods, this was confusing. Jason started to explain, "I was in my room, polishing my sword because Piper and Hazel were using the training room. That's all. One minute I'm sitting on my bed and the next –" He felt it would be best to stop there from the murderous look Percy was giving him. It felt weird seeing his face from outside his body. He wondered if this is what he normally looked like when he got angry.

"Percy?"

"I ended up exactly where Jason stopped," Percy said, "I was in his room and suddenly I was holding a sword and I was so surprised I dropped it – sorry, man – and then I looked at myself I the mirror and I was in Jason's body." Percy shook his head. "This is the weirdest thing that has ever happened to me. And a lot of weird stuff's happened to me."

"We need to look at the old myths," Annabeth said decisively, slipping into Daughter of Athena mode, "Find out who could do this. We need to get to the bottom of this."

She reached out like she wanted to take Percy's hand but then stopped herself. Holding hands seemed wrong when Percy was in Jason's body so she lamely patted his bicep instead.

"Let's go."