Percy, Thalia, and Nico betrayed

The switch in plans

Percy and Frank were, at the moment, playing video games. Also known as, Mario Kart. Percy was on a winning streak, and Frank was starting to get desperate. He jabbed at the buttons as he twisted the joystick.
Then he yelled in frustration.
Percy had, once again, won.
"Percy, you were in Tartarus for 5 years. How in the name of the gods are you so good at this game?" Frank yelled at the smirking Percy.
"I, honestly, have no idea, Frank," Percy smiled cheekily. Frank groaned, and checked his watch.
"Oh! Percy, we have to go meet up with the others. It's been a week, now, and it's 10:00," Frank said, putting away his controller. Percy nodded, and turned off the game.
They walked towards Zeus' Fist, where we saw Piper, Leo, Calypso, Nico, Jason, Will, Thalia, Hazel, and Annabeth waiting for them. Frank ran forward to Hazel, who embraced the archer. Percy smiled. Even if they do argue sometimes, they really do love each other. That's when a force hit him.
Percy was knocked backwards and on to his back as a floof of hair was pushed onto his neck.
"Percy!!" Nico yelled, and Percy laughed as he hugged his boyfriend tighter.
"Nico! How has the last week been for you?" Percy asked as he picked Nico up and carried him bridal-style back to the group.
"It was okay. Jason tried to hit on me-" before anything else could be said, Percy cut him off.
"He did WHAT?!?!" He yelled and stomped over to Jason, but halfway there was stopped by Nico jumping on his back. He fell backwards, and his head landed in Nico's lap. Percy blushed.
"You didn't let me finish, Percy," Nico whined, "I was going to say that I beat his ass!"
Percy grinned. He should have known not to underestimate the son of Hades. He hugged the death boy, but he pulled away and kissed Percy. Percy immediately kissed back. After a few seconds, the broke apart and smiled. Then, they got up and walked to the group, finding a beaming Frank, Hazel, Leo, Piper, Thalia, and Calypso, and a jealous looking Jason, Will, and Annabeth.
"Hey guys!" Percy waved. Annabeth blew him a kiss, but Percy and Nico both glared at her. She cowered back.
"Hey!" Thalia said, running towards her best friends. They all hugged, and when they pulled back, everyone was waiting.
"Okay! So, now we need to switch up the pairs-" a yell was heard, cutting off Percy's voice.
"Percy! You guys have run out of time!" It was Rachel, her frizzy red hair bouncing as she ran.
"Rachel? What's happened?" Percy asked, and Rachel burst into tears.
"I'm sorry, I tried to hold them back! It's your call, the one from the prophecy. It has begun!" She said through her tears.
Leo's head snapped up, eyes wide. Everyone else also snapped theirs heads up, and immediately drew any weapon they had. Calypso led Rachel away to safety, and the group of 10 ran to the hill.
They saw herds of all kinds of monsters from the underworld.
"What. The. Heck," Leo said, fire extinguished from his hands.
"I.... have no idea," Thalia replied, looking over the herd.
Percy sighed, "Okay, guys. There's only one option. I have the feeling whoever moves first loses, so stay still, and wait for the first move. If they attack, attach them back. If someone is injured, either help them through the border or make sure no animal of monster gets to them."
"Right!" They all shouted, and they stood, weapons drawn, still and facing the herd, as the waves of the lake started to roar.