A/N: Because I'll never get over the fact that Percy's first official "I love you" was from Piper's perspective. Guys, this is probably my favorite thing I've ever written for this pairing. I was inspired like, two hours ago and wrote it all in one sitting. I sincerely hope you enjoy this.

Ever since the Labyrinth, let alone Tartarus, Percy had held a disdain for being underground. It felt restrictive, and he could never shake the fear that he would be stuck down there forever, wandering the endless darkness.

The only thing really keeping him from turning and running in the opposite direction was Annabeth's hand, steady as always, anchoring him to the ground. He smiled slightly. No matter how hard he'd try, he'd never be able to express to her just how important she was to him.

Suddenly, a small gasp of air caught his attention, and he glanced down at Annabeth just in time to see her wince in pain. Percy furrowed his brow in concern and opened his mouth to ask Piper if they could stop for a moment. He didn't get the chance though, because Piper stopped abruptly and held up her hand.

"Wait," she said. "Wait." They stood in silence for a long time, and Percy and Annabeth quickly met eyes. "I'm going to look ahead," Piper continued, turning to face the two of them. "Wait here." Then she hurried up the tunnel, disappearing into the dark.

Percy turned to Annabeth.

"What is it?" he asked. Annabeth shook her head.

"It's nothing," she replied. "My stupid ankle still hasn't healed. I think Tartarus did something to it permanently."

"Do you need to sit down?" Percy asked. Annabeth shrugged indifferently.

"I don't know," she said back.

"You should," Percy said firmly. "Save your strength." Annabeth gave him a strained smile.

"I hate it when you make sense." Percy chuckled.

"Yeah, well. I do too sometimes." He guided her toward a large boulder, and Annabeth sat down, a sigh of relief escaping her lips.

"I take it back," she said. "My life is infinitely better when you make sense." Percy smiled and sat down next to her, wrapping an arm around her waist, and Annabeth rested her head on his shoulder.

"Feel better then?"

"Yes." The two of them sat in silence, listening to the echo of water dripping from the ceiling.

"Know what this reminds me of?" Percy whispers.

"Hmm?"

"The labyrinth. Remember being stuck underground? For hours at a time?" Annabeth let out a small laugh.

"Gods that was forever ago," she said, and then she looked up at him, meeting his eyes. "Though I like this situation much better." Percy smiled.

"How come?"

"Because we aren't fighting. We finally figured out us."

"Us," Percy repeated, his heart skipping a beat at the word. "We do make a pretty good us,don't we?" Annabeth squeezed his hand.

"We do."

A few more moments passed, and then Annabeth laughed, though she tried to stifle it.

"What?" Percy asked, looking down at her.

"It's just-" Annabeth broke off and let out a few more giggles. "It's just that we had such a big rivalry back then. I swear, Percy, we were at each other's throats twenty four seven" Percy smiled fondly.

"We still are," he said. "But in the best way. I'd consider us in a perpetual state of friendly competition." Annabeth laughed again.

"I like it," she said. "Friendly competition. Don't expect to win any time soon." Percy smirked and nudged her with his shoulder.

"Don't hold your breath," he said. "You have no idea what I'm capable of."

"I absolutely know what you're capapble of," Annabeth replied, nudging him back. "And I have a million plans for a counter attack."

"I'd expect nothing less," Percy said as he placed a kiss on her head.

"Athena always has a plan," Annabeth said. "You should know by now that..." she trails off, and sits up, inhaling sharply.

"What?" Percy said, slightly alarmed. Slowly, Annabeth stood up and moved across the cave. "Annabeth, what is it?"

Annabeth shook her head.

"Come look at this," she said in awe, and Percy obeyed, standing up and walking over to where she was looking. When he saw what she was referring to, his mouth fell open.

"Woah."

Right in front of them, long, jagged white grooves rested on the tunnel wall. The groves were huge, nearly as long as Tyson, and several inches deep. He imagined his father, the force which he must have had to make markings this pronounced. Annabeth's voice brought him back to reality, and he saw her reach up, running her hands along the markings.

"This is the place. Percy, these are the trident marks of Poseidon."

Hesitantly, Percy touched the marks as well, feeling the scars left by his father's anger. "He must have been using his extra-extra large trident." Out of the corner of his eye, he saw Annabeth smile briefly.

"This is where he struck the earth," she said in an almost reverent tone. "Where he made a saltwater spring appear when he had the contest with my mom to sponsor Athens."

And then it dawned on him. This wasn't just any old mark. This was the beginning of a millenia-long fight. This was the reason he and Annabeth were never supposed to be friends, let alone a couple. A memory surfaced in his mind. Of the two of them, at age twelve, sitting in a zoo truck to Los Angeles.

We're just not supposed to get along, she'd said back then. Our parents are rivals. And then later, I just know I'll fight by your side.

"So this is where the rivalry started," Percy said quietly.

"Yeah," Annabeth responded, still in that same reverent tone. They dropped their hands from the stone and met one another's eyes. Annabeth's, stormy gray as always, were softer than usual.

How many times had he stared into those eyes? A thousand? A million? He didn't know for sure, but he'd seen them enough to almost always be able to tell what she was thinking. And she was surely able to do the same. It sometimes shocked him, realizing how long they had been together, how much they had done and seen together. It had always been the two of them, hadn't it?

And Percy was certain it always would be.

It hit him, then. The realization that he was absolutely in love with Annabeth Chase. He had been for years now. And he still hadn't told her.

He'd shown it of course. How many things had he done because he loved her? Their whole entire experience in Tartarus happened because of how much he loved her. Hades, she'd been his tether to mortality when he took on the curse of Achilles. Now he has every intention of telling her.

But first he pulls her in for a kiss.

This kiss wasn't like any other he'd given her. It was sweet as well as passionate, with an added desperation that he couldn't quite express. After all, who knew what the outcome of this next battle would be?

Annabeth wrapped her arms around him tightly, and his hands found their way to her face, tangling in her loose hair. He tried to pour every possible feeling into the kiss, hoping beyond hope that she would know just how much love he had for her.

Percy could have stayed there forever, holding her, but eventually, they had to break apart. Percy pulled away and looked at his girlfriend, her mouth slightly open, breathing deeply.

"The rivalry ends here," Percy murmured. "I love you, Wise Girl."

A small, gasping sigh escaped Annabeth's lips, like something had melted inside her, and she pulled him in for a tight embrace.

They didn't need to say anything else.

She knew. He knew.

And when Piper finally came back to lead them to the giants, they followed hand in hand, ready to face whatever was to come.

A/N: Thank you so very much for reading this. Please leave a review and tell me what you think. I would love your feedback!