At the tower, Clint and Natasha checked their weapons, confused why they didn't work on the creatures they encountered. Percy was watching the news.

"Is Percy Jackson the newest addition to the Avengers? The last time Percy Jackson was in the public's eye, he was part of the kidnapping spree with two other individuals: Annabeth Chase and Grover Underwood." With a sigh, Percy turned off the T.V.

Tony walked towards him while drinking some wine. "Kidnapping, huh? Any good memories? Oh, I don't know? Facing kidnappers face to face with a gun? I watched the footage. Could work on your shooting, though."

Percy snorted. "I've never shot a gun. I'm surprised you can even see the hellhounds if you think I was using a gun."

Tony arched an eyebrow. "So what do you use? A pitchfork?"

Percy shook his head. "Nah, pitchforks aren't really my thing. It's more of my dad's style."

Tony just stared. "Kid, you've really got to work on your sarcasm."

Percy shrugged and helped himself to some popcorn. With a leveled gaze, Natasha asked Percy a question. "How did Thor, Stark and you defeat those hellhounds? Our weapons didn't work. And where did you get the sword back in Central Park?"

"Yeah, how do you know our resident thunder god?"

Percy frowned. "Thunder god? I don't really get along with gods. Especially the Thunder God. He's so full of himself."

He looked up. "No offence, of course."

Thor paid no notice to that.

He clapped Percy on the back. "Don't worry Perseus! I admire your feat. It is the talk of the grand halls back at Asgard!"

"Come on kid, give us some hints. How did that guy get in the blonde kid's body? And how did he freeze time? Don't think I didn't notice!" Tony urged.

Thor looked confused. "You don't know? Percy here is the son of one of the gods!"

"What?" Tony looked lost.

"Kid, you really got some explaining to do." Tony said.

Percy flopped back on the couch. "One thing, don't ask me who pater is, I don't know. But that guy back there is my grandfather. I mean the guy in him. The blond guy, is well, dead. I don't know how he's here. Last summer he was supposed to be gone. Forever."

"Well, that doesn't help us very much."

"Do you know why Clint's and my weapons don't work?" Natasha questioned.

"Those monsters can only be killed by certain weapons. Celestial bronze and Imperial gold are two of them. Fire and thunder can also work."

"Like your sword you pulled back there?"

Percy nodded his head. "Celestial bronze."

"Where did you get it?" Tony asked. "You pulled it out of thin air back in the Park."

Percy smiled and took out a ballpoint pen.

"I'm not kidding."

Percy smiled and nodded at the pen again.

"Kid, that's a one dollar pen you can get in a shop."

Percy took of the cap. It expanded, glowing. Bruce and Tony took a step forward to examine the metal.

"Kid, what is this?" Tony asked.

"Celestial Bronze," Percy said. "It's enchanted so I can never lose it."

Percy capped it and out it in his pocket.

Tony rubbed the back of his neck. "Well, that's mind blowing." Suddenly he lit up like a kid on Christmas morning. He looked to Natasha and opened his mouth. "Can-

"I'll work on it." Natasha promised.

"Where can S.H.I.E.L.D get these metals?" Natasha asked Percy.

Percy sat up. "You can't. I don't know about Imperial gold, but Celestial bronze is mined from Mount Olympus itself. Besides, there are more important people who need that." "More important people?"

"Yeah, family. From what I've seen, S.H.I.E.L.D has all the gadgets they want. The Celestial bronze and Imperial gold are rare metals. And my family needs them."

"So why not have them help us against your grandfather if he's the bad side of your family."

Percy gaze hardened. "No way. My family has suffered through too many things. I'm leaving them out of this."

Bruce came forward. "Well, we know that you grandfather is on the other side. What was his name again? You called him Kro-something?"

"Kronos." Percy supplied.

"Kronos. Like the guy in the Greek myth?"

"Same and only. Even after thousands of years, he still wants to gobble up his children. Or topple their thrones. He never said which one he wanted to do this time."

Tony came to a realization. "Greek God…"

Percy scowled. "Titan."

"Titan. Which means you are…"

"Percy Jackson, son of Poseidon."

All the avengers couldn't believe their ears except Thor who was eating a Pop tart.

"Your not really a god, are you?"

"Only a demigod."

"And all your family…."

"Are demigods," Percy finished. "I do have one other half-brother who's a Cyclopes."

"And you have other brothers too?"

Percy shook his head. "Demigods are powerful. They can exist in the godly world and the mortal world. Children of the big three- Hade, Zeus and Poseidon- are especially powerful. After World War two, they promised no to have any more children."

"World War two?" Steve asked, joining the conversation.

"Yeah, it was a war between the Children of the big three. Hades on one side and Zeus and Poseidon on the other. Hades lost and Zeus and Poseidon forced him into an agreement. They made a pact on the Styx, which is a binding oath. If you break it… let's just say there are worst things than death."

"I noticed you're here," Tony said.

Percy shrugged. "They're gods, so they got off easy."

Steve frowned. "That's not right. No matter how powerful they are they can't break the rules."

"I've learned a lot about what the gods can do and what they can't. And breaking the oath is something they can do."

Tony shook his head. " Kid, you have one messed up family."

Percy smiled. "You don't know the half of it."

"Well." Tony said, extending an arm. "Time to give you the grand tour around Stark Tower. You'll love it."

The cavern was pitch black. It was cold and for all Annabeth knew, no way out.

She was alone, for none of her supplies were with her. Not her phone or her knife. A sinister feeling crept in and Annabeth shivered to keep herself warm. All she could remember was closing the Doors of Death with Percy on the other side.

"Patient, Annabeth," said a voice Annabeth didn't recognize.

"Who are you?" she yelled. "Where's Percy?"

The voice chuckled. "You are only the first stage. The second stage will happen soon, I promise. The Giants were smart, targeting the roots of the Gods and awakening Gaea. But there is always something better."

"Percy will stop you!" she yelled with complete determination. "He will always stop you."

"Such faith you have Annabeth. Too bad you and Percy will die together just as Gaea wished. It was one of her better ideas." The voice said, fading.

Annabeth's eyes widened. "Tartarus." She whispered in horror.