AU: Okay, so I found this headcanon on google and it really broke my heart. I imagined it out completely after that and wanted to write this story long ago but I couldn't find that headcanon again, so I just decided to get on with it and wrote the headcanon again myself.

The story is mine, the headcanon is not and please don't hate me, because I really love Percabeth, I really do. It's just that I couldn't resist writing it. Also, this is my first story.

Headcanon:

Annabeth walked into her room to see Luke standing there. "L-Luke?" she whispered.

"Annabeth" he said smiling, "it's me. I'm back!" he said spreading his arms wide.

Annabeth hesitated. In a few long strides, he crossed the room and kissed her. Annabeth resisted but then gave in.

"Hey Annabeth" they both turned around to see Percy standing at the door. His eyes went from Annabeth to Luke and back again. Then he turned around and walked away.

"Wait, Percy!" Annabeth shouted as she ran after him, "I can explain-"

"You were kissing him weren't you?" he asked

Annabeth looked down at her feet "Y-yes"

She looked up to see tears streaming down his eyes. He put a hand in his pocket and took out something. Her eyes widened as she saw the ring inside it. She covered her mouth with her hand. He threw the box down and kicked it in the dirt. Then he ran away.

And Percy Jackson was never seen again.

Story:

Annabeth sat behind some rocks near the sea shore, looking at the horizon.

She was waiting; waiting for someone she knew in a small part of her heart would never come. The pained, betrayed look in his eyes still haunted her. She had been sitting in the same position for days, refusing to move or talk to anyone to tried to console her or make her forget him. She refused to eat, hadn't even taken any notice when Chiron came to see her.

There was a deep ache in her heart. She longed to see him, talk to him, and stare into those sea-green eyes of his. She couldn't believe what was happening to her. Oh, why had Luke come back? Yes, she loved Luke but he was gone and she had learned to live without him. But Percy was her life. Ever since that day she saw him for the first time.

She remembered their whole history together. The fights, the hatred she felt for him when she found he was a son of Poseidon, the disappointment, the way he got on her nerves, how cute he looked with that goofy smile of his. Since that first quest, they had gone through a lot together. And now one was a part of the other. It had been impossible to separate them. Monsters, Titans, Gaea, even her own mother had tried. They had gone through Tartarus together. And now a simple mistake had set them apart.

Her mind flashed with every memory she had of him as she got up and made her way towards the water. Her limbs were stiff but she hardly noticed. The ocean scent made her feel Percy's presence. How often had they come here together?

She stepped onto the waves and walked deeper and deeper inside the water. She wanted to be near him one last time. And as her head submerged and her lungs filled with water, she felt like he was right there with her.

There was a smile on her lips as she took her last breath.

Percy lay deep under the ocean bed, among corals and seaweed and tried not to think of her. Everything reminded him of her. Her smile, her grace, her striking grey eyes, and then her betrayal. Percy hated Luke with all his heart. He had died a hero, respected and honored, so why did he have to come back?

And just when Percy had finally been happy, about to propose to the girl he loved more than his own life, his world had come crashing down. Oh, why couldn't he be happy for once? Was it too much to ask?

Percy was brooding over his faith and feeling sorry for himself when he saw a dark shadow above him. As it drifted nearer, he realized it was a body, a human body.

He swam over to where it was floating in the water, sinking slowly down, and he felt his heart break into pieces once again.

There was his Annabeth, her face chalk white, lips blue and her hair flowing wildly around her. There was a smile on her face and she was dead.

His heart thumping wildly, Percy wrapped his arms around her waist and swam as fast as he could towards the shore. He wanted to save her, in any way possible, but he knew there was no hope. She was gone, never to come back.

He broke above the surface of water and laid her on the sand. For a long while he sat there, kneeling beside her, cradling her face in his hands, tears flowing freely, relentlessly from his eyes. No matter what had happened in the past few days, he loved her and seeing her like that, he felt as if a part of him was dying.

He felt anger bubbling inside him, along with grief. Who had dared hurt her like that? For it didn't occur to him that she could have let that happen of her own free will. No, something must have happened. And he was going to find whoever did this to her and he wasn't going to rest until it was done.

Before it had been a small consolation for him that at least she was happy, though he tried not to think who it was who made her feel that way. And now, she was gone…

"Percy?" he heard a voice behind him. It was Piper. "Oh, thank god you're back. Annabeth has been-"Then she stopped abruptly as she noticed who lay beside him. Her hand flew to her mouth in shock.

"A-Annabeth?" she whispered as her knees gave away and she landed beside him, staring at Annabeth's lifeless body, sobs beginning to shake her petite frame.

Percy silently got up and started to walk away, heading back towards the ocean.

"Wait, where are you going?" Piper questioned behind him. When he didn't respond, she got up and pulled him back. "You know why she did this, don't you?"

"What are you talking about?" Piper almost recoiled from the fierce look on his face, "She was murdered. Thrown into the ocean to the water's mercy."

"You don't understand, Percy!" Piper threw her hands up in the air in exasperation.

"She did this for YOU! She couldn't stand being apart from you. I know, I felt the heartbreak she felt." She shouted.

It wasn't possible, yet Percy knew Piper was right. She was the daughter of the goddess of love after all.

Percy felt the world around him swinging, turning upside down. Flashes of her smiling face appeared before him. He felt like drowning, though he knew he couldn't drown, being the son of Poseidon.

His Wise girl was gone, gone.

Piper watched as realization slowly dawned on the raven-haired boy's features, bringing with it anguish such as never witnessed before. She felt it keenly, She had never seen anyone as broken as Percy looked at that moment. His shoulders slumped, his eyes clouded with pain.

Suddenly his head shot up. Without thinking of the consequences, he brought out Riptide and in one skilled stroke, brought death upon himself.

Piper watched with horrified eyes as his form fell backwards and his head came to rest on Annabeth's hand. Blood was rapidly pooling around him, staining his shirt, making it seem all the more real. His breath came out in shallow gasps and his skin got paler by the second as he lost more blood.

"Annabeth" He whispered one last time as his eyes closed and his spirit finally left his body.

Piper slowly walked back towards the big house, to announce to everyone that their heroes, who had gone through so much together, were dead.

As she saw their shrouds burning that night, golden flames engulfing them, and mourning campers surrounding them, she realized something. Even death could not separate those two; eventually they always found their way back to one another. They were made for each other, the perfect fit. They knew the other better than their own selves. And she knew they weren't really gone, their memories would always be alive in their friends' hearts, never to be forgotten.

Somehow she felt that somewhere in Elysium, Annabeth was waiting for Percy and that they would finally get the peace they deserved, in death.