"Annabeth was too stunned to move. She felt that if she got any closer to him, all the molecules in her body might combust. She'd secretly had a crush on him since they were twelve years old. Last summer, she'd fallen for him hard. They'd been a happy couple for four months- and then he'd disappeared.
During their separation, something happened to Annabeth's feelings. They'd grown painfully intense- like she'd been forced to withdraw from a life-saving medication. Now she wasn't sure which was more excruciating- living with that horrible absence, or being with him again.
The praetor Reyna straightened. With apparent reluctance, she turned towards Jason.
"Jason Grace, my former colleague…" She spoke the word colleague like it was a dangerous thing. "I welcome you home. And these, your friends-"
Annabeth didn't mean to, but she surged forwards."

Before she could kiss him, he backed away warily. That shook her from her stupor. Backed away...?
Oh, no.
That didn't- he couldn't have- Percy-
Annabeth's eyes widened in horror and her eyes stung. Percy didn't remember her. All those years they spent together we wasted away like they didn't matter. They vanished, all those memories that drew the two of them together were simply gone. Now they had to start from scratch on this stupid journey. When she got the chance she was going to punch Hera in her royal face, cows or not. Maybe Aphrodite, too.
She blinked back tears. "Hey, Percy…" she choked out, trying not to let her voice crack, "you don't remember me, huh?"

PERCY

His face visibly darkened. The son of Poseidon was well aware of his missing memories, and the fact that he came from somewhere else- a Greek somewhere else, the place that this big trireme came from. The look on the girl's face- it made him feel guilty for not remembering anything, even if it wasn't his fault.
"I, uh, I'm sorry," Percy stammered. "I don't know, um, exactly who you are."
The other bit her lip and blinked, her hands clenching into fists that probably wanted to judo-flip him or something. Another girl with kaleidoscope eyes and hair braided down took the former's arm.
"Let's just head back to the ship, okay?" she said.
The blonde one seemed reluctant to leave, but she just nodded, walking stiffly back to the rope ladder, with the other in tow.
The rest of the meet n' greet went by in a blur- Percy didn't pay much attention to it, mostly just sort of nodded along. The first girl who seemed to be close to him eventually came back down, but neither he or she talked to each other, even sort of wove around when they came in close quarters.

[… after the whole ballistae scenario …]

LEO

He watched as Frank finally managed to haul a resisting Jackson onto the fleeing trireme, who landed with a thump.
"Ow!"
"Sorry," the son of Mars said.

"Leo wished he could invent a time machine. He'd go back two hours and undo what happened. Either that, or he could invent a Slap-Leo-in-the-Face machine to punish himself, though he doubted it would hurt as badly as the look Annabeth was giving him.

[...]

"Leo's heart stumbled. "Is Jason-?"
"He's resting," Annabeth said. "Piper's keeping an eye on him, but he should be fine."
Percy gave him a hard look. "Annabeth says you did fire the ballista?" Since when did he learn her name? Probably when they were downstairs, he thought.
"Man, I-I don't understand how it happened. I'm so sorry-"
"Sorry?" Percy growled.
Annabeth put a hand on her boyfriend's chest[…]"

but he swatted it away. He looked like he was thinking of a million ways to chew him out for what happened back in New Rome, which Leo honestley didn't need to be reminded of. Then he rounded on Annabeth.
"And you. You were talking with Reyna, right? What were you discussing?"
"I-"
She was interrupted my Percy waving a dismissive hand. He seemed to be trying to collect himself. "Okay, that was mean. Sorry. I just- sorry."
He just shook his head and walked heavily (but not quite stomping) back down the stairs, fists clenched.

Annabeth turned and reached out, as if she was going to follow him but quickly realized her current situation with her boyfriend and canceled the gesture.

"We'll figure it out later. Right now, we have to regroup and make a plan. What's the situation with the ship?"
Leo's legs trembled. The way Percy had looked at him made him feel the same as when Jason summoned lightning. Leo's skin tingled, and every instinct in his body screamed, Duck!

[…]

ANNABETH

Annabeth sat in her room, absentmindedly watching the screen of her Daedalus laptop. Frank had just come by asking for advice on how to escape Chinese handcuffs, and now that he'd left she had some thinking time for herself. Even now, Percy didn't seem to recognize Annabeth. In fact, the two didn't talk much as of now, and when they did the two were rather awkward.
Hopefully this quest would bring the two of them back together, and maybe a good knock on the head would get him to remember though she doubted it. Her Seaweed Brain was lost. Annabeth bit her lip as a few rebellious tears threatened to spill. She wiped her eyes, closed her laptop and slid under the blankets. There was no point in sulking about it. The team had an apocalypse to stop.

(A NOTE TO THOSE FOLLOWING: This story is completed. Percy will probably have been friends with all the others by the middle and end, and there would not have been enough difference in the other Percabeth scenes to make the fanfiction.

EDIT: Haha nevermind.)