As they discussed plans, Percy couldn't help but feel as if something was wrong. His instincts were telling him that something wasn't right.

He quickly scanned the shadows, to see if anybody was hiding in them, but found nothing.

No one is listening in... unless Annabeth is using her invisibility hat.

But then why do I feel like something isn't right? It's not because of the switch... so then what is it?

"-cy," Nico said, snapping his fingers in Percy's face. "Percy."

"What?" he asked, slightly startled.

"I asked what was wrong. You're acting weird."

"I... I don't know. Something just feels off."

Nico looked around. "Maybe we shouldn't be here."

Percy nodded. "Let's continue this somewhere else."

The two left the Big House and headed towards Cabin Thirteen, not noticing the figure that had been able to hide itself from Percy's senses.

"Nico, we can't tell anyone about this now. Chiron knows, but that's it. If another war is going to start, they're bound to have spies in the camp," Percy said. "They'll take advantage of what's happened and attack before we're ready. But that just means that we'll have to work harder, right?"

Nico nodded. "We should continue teaching each other now... well, my powers consist of shadow traveling, being able to hide myself in the shadows, raising the dead, etcetera. So what do you want to do next?"

"Which do you think should be the next thing for me to learn?" Percy asked, glancing up at the ceiling.

"Maybe hiding yourself and other things," Nico muttered. "Since I just taught you how to feel if someone is in the shadows. Plus, that should come before shadow traveling."

Percy nodded. "Right, so..."

"It's hard to explain, but I'll try. Basically," Nico said, backing into a dark corner. "You can still see me normally, can't you?"

"Yeah, I can."

"The idea is that the shadows would 'cling' to you rather than avoid you, and would help you hide in the shadows."

Percy nodded like he understood, but he really didn't. I'll figure it out, he thought to himself before walking into a dark corner and trying to do what Nico explained. "Did I do it?"

"No," Nico answered. "Try it again."

Percy focused on the shadows, and tried to make them pull towards him. He felt colder for a second, but then it stopped.

"You had it for a second," Nico pointed out. "Now just use that to be able to do it for longer."

They practiced for a while, until Percy could do it without breaking a sweat.

"Okay, now onto mine," Percy said. "Let's keep doing what we did with the glass of water, but try to do more than just drop it on my head. Try to use it as a weapon."

They walked into the bathroom and Percy grabbed a cup, filling it with water from the sink. He set it down on the counter and Nico concentrated on it, making it rise from the cup and slowly started circling around him.

Percy grinned. "Perfect."

Nico then directed the stream of water right into Percy's chest.

"That was cold," he complained as he dried himself off.

"Get used to it," Nico replied. "What's next?"

Percy was silent for a minute, before deciding. "We take it to a bigger scale, of course. We'll have to wait until after curfew, though, that way we won't be found."

"That's where you come in," Nico said almost immediately. "You'll hide us from the harpies. So it's a test, pretty much."

Percy muttered something about tests, but then looked up. "Okay. One thing you should concentrate on is-"

The two boys were startled when someone started pounding on the cabin door. "Percy!" someone yelled.

"Grover," Percy muttered, his eyes wide. "Hey, Nico..."

"What?" Nico asked, opening the bathroom door.

"If Grover had an empathy link with me before all of this, do you think it'll still be there?"

Nico shook his head. "You died. Grover should be dead, too, if the empathy link was still intact. It must've been broken before you died."

"Unless we both did die... and when I was brought back so was he..."

"Empathy links connect minds, not souls," Nico said.

"But then why is it that if one person died then so would the other?" Percy asked.

"I don't know," Nico replied. "But you better open that door before Grover breaks it off."

"He's calling for you," Percy replied, leaving the bathroom and sitting on Nico's bed.

Nico sighed but opened the door. "Grover!" he said. "What are you doing here?"

"I've been looking all over for you, Perce!" Grover said. "Where've you been?"

"I've been here the whole time," Nico said, opening the door wider. "So what's up?"

"There's going to be a meeting, but that's not what I came here for. Everyone is telling me that you were killed and then brought back by Nico," the satyr said before pausing, as if waiting for confirmation.

"I'm sitting right here," Percy said. "If you have questions, ask them. If you don't, then we have things to do."

"What he means is, no, Nico did not kill me, and yes, he did bring me back," Nico said, shooting a glare at Percy but silently applauding his act. It wasn't exactly right, but it was close enough.

Percy resisted the urge to grin and instead returned the glare.

"Right, so what were you saying?" Nico asked.

"The empathy link was broken, I can feel it," Grover explained. "We're not connected."

Thank the gods, Percy and Nico both thought at the same time.

"How would it have broken?" Nico asked.

"They don't break when one of the people involved dies," Grover said. "Usually the second person dies, as well. So it was broken before that. But how long?"

Percy remembered calling out to Grover not too long after he was attacked, and he knew that it was still intact because the satyr had come running, but there wasn't much time between that and when he died. So then when...?

"It couldn't have been that long," Nico said, hoping Percy could provide him with some information.

Percy stood up and walked over to the door and faced Grover. "You're suggesting that it was broken in the second between when Percy was attacked and when he died?" he asked.

"That's exactly what I'm saying," Grover replied. "The only question is... why? And by whom?"