"Hey, Percy…" Nico said as he stared into the deep blue sky as it turns darker and darker, the sun setting into the ocean and stars coming out, one by one. "What is it?" Percy replied, digging his fingers into the sand as the sea water hits his feet. "Can you ask your dad something for me?" he asked, looking into Percy's eyes. "And Jason too…" he looked behind him, standing tall, and wind hitting his face and blowing his hair.

"What do you want to ask?" they said in unison. "Well…" Nico hesitated. "Why is the ocean so deep? And why can't the sky have an end? I mean, after the sky is the outer-space, right? Where is the border in between? And also, why can't the ocean be a bit more shallow?" he asked, looking at both of them with innocent eyes, like he could never kill anyone nor anything.

"Well… That's just how it is… If the ocean is anymore shallow, then there wouldn't be enough space for any other creatures to live in the ocean, right?"

"Actually, there IS a border between the sky and the outer-space. The atmosphere in between is the border, but you just can't see it…"

"Really now..?" Nico doubted. But he wouldn't doubt the two good friends he had. "Why aren't you guys with your girlfriends? Annabeth and Piper are there… Chatting happily and eating snacks under a tree like they're… Never mind…" he wanted to say, 'as if they're dating… or something' but stopped himself before it's said. "It's almost time for dinner… I'm going ahead… You guys can enjoy the sunset a little bit longer… bye"

Nico lay in his bed soundlessly. No matter how many hours passed, he couldn't sleep. 'Why did I ask such an idiotic question? Those stuff could be thought of logically…' he didn't feel comfortable thinking about how he hadn't graduated middle school at that time. Or he HAD but none of the lectures seem to stay in his mind. So, he decided to take a breather.

Somehow, his feet brought him into the woods. He was just wandering around aimlessly when he heard voices coming from somewhere, deeper into the forest. He suspected that it was the forest creatures, but he couldn't ignore his curious heart, so he followed the voices' source. There, he found Percy and Jason.

"No! I wouldn't hand him to you!"

"What makes you say that? Because you broke up with Annabeth, she dated Reyna, and then Piper took interest! She was your girlfriend, for god's sake!"

"What's so wrong about it?! SHE was the one who DUMPED ME! Plus, he's MY Nico!"

"He's not only yours, Perce. He's also mine!"

"No! I won't share him with you!"

"Well then, LET'S SEE WHO HE PICKS! HE HIMSELF SHOULD DECIDE!"

They began screaming and then lowering their voices again, to the point where Nico couldn't hear them at all. Hearing that, he decided to return to his room. 'Has it been this way..? All this time, I thought they were on good terms but… does being with me always create such fights? Will their friendship wither… because of me..? If I'm only good at destroying relationships, then I...'

The next day, Percy and Jason were together, like real buddies. They went here and there and everywhere like always. When they came to the Hades cabin, they called out to Nico. "Hey, Nico! Wake up! It's already 10 AM!"

"Nico! Come out! Let's go to that place I told you about!"

No response.

"Nico! Let's go!"

The air was still. After a while, they decided to open the door. It wasn't locked, which is very rare. They searched the whole cabin, but Nico was nowhere to be found. Where could he be? No one saw him at camp either. When Jason asked Reyna, she said that Nico's not in camp Jupiter either. Percy and Jason both got into a conclusion; Nico was missing.

Later, Chiron gave Percy and Jason a quest to find Nico and pick up some demigods on the way, if they find any. But two people won't suffice. So, they picked Leo for the third person.