A/N: Hey guys! Back again. Sorry I haven't been very active recently. I've been quite busy. Anyway, here's an idea I had. Also I'm kinda obsessed with the Percy Jackson series and Gravity Falls at the moment and probably will be for awhile. So, yeah! On with the chapter.

I don't own Gravity Falls or Percy Jackson.

Leo was having a nightmare. It was a common thing, being a demigod but this one was... different. Weirder than usual. Had a different feel to it. Everything was grey. There was nothing around. Then, a flash of light. A... yellow nacho with an eye, a bow and a hat was there. Leo was suspicious. The triangle looked around.

"What a mind you got here!" the triangle said.

"Umm.. Thanks, I guess? Who are you?" Leo asked curiously.

"The name's Cipher. Bill Cipher. You're Leo Valdez," Bill floated in front of Leo.

"What... How?" Leo spluttered.

"I see all, kid!" Bill said. "Know all!"

Now, Leo was really suspicious. "Why are you in my mind Bill?"

"Wow, straight to the point! You're like Pine Tree. Alright, I wanna make a deal with you!" Bill stuck out his hand, wrapped in blue flames. "I'll save you and your friends from old Earth Face! All I need is one little thing! You all give my your energy so I can take over the world! With all the energy I'd get from you halflings I'd be able to break out of the Dreamscape without old Sixer's rift!"

'Who are Sixer and Pine Tree?' Leo wondered to himself. His thoughts wandered to the deal. He made a decision.

"No," Leo said firmly.

"No?" Bill looked shocked for half a second and then returned to neutral. He retracted his hand. The flames went out. "Why not? It could stop you from dying against Earth Face!" Bill said, trying to convince Leo.

"No, Bill! I don't take deals from untrustworthy demons or whatever you are! I'm not Athena's son but I'm not that stupid!" Leo shouted, filled with an anger he hadn't felt before. This demon invaded his mind. Bill turned red and his voice was deeper.

"You'll regret what you said, Flame! I mean it! I'm coming for you and your friends! I suggest you land your ship before I knock it out of the sky!" Bill returned to normal.

"Leave my mind, Cipher!" Leo shouted angrily.

"No need to tell me, Flame! You're waking up now!" Bill laughed. With that he disappeared. Leo woke with a start. Outside, the wind was howling. The ship was groaning and creaking. He hurried into his clothes. He rushed into the deck. The Argo was flying quite low. He could see huge waves hitting the hull. The waves were slowly rising. He could see Jason trying to make ethereal wind lessen. Percy the same with the water. Despite their best efforts, the elements wouldn't obey. They were keeping the ship steady. They would all be dead now if not for them. Leo could see they were very tired. How long had they been out here? He rushed to the helm were Annabeth was trying to steer the ship. A cold feeling settled into the pit of Leo's stomach.

"Bill..." he whispered. He looked around and spotted the coast.

"Annabeth! Fly towards land! We're stopping! Percy and Jason won't be able to keep the ship stable for long!" Leo shouted to Annabeth over the wind. Her hair was whipping around her face. She nodded her head and turned the ship toward the coast. The wind was getting stronger, the waves taller. All at once. Leo turned around and realised Percy and Jason had both collapsed. Percy looked like he had hit his head against the mast. Frank, Hazel and Piper came up above deck. Leo caught their attention and pointed at Percy and Jason. The three ran as best they could against the wind towards them. Leo turned back to the controls. They were flying over land now. The waves weren't assaulting the ship anymore. The wind was strong though and Leo heard the ship creak and groan.

"We have to land, now!" Leo shouted at Annabeth. He scanned the area. He pointed at a clearing in the trees. "There!" The ship started to descend. Leo figured Annabeth had it so went to check on Jason and Percy. Jason was conscious but still looked pretty bad. Percy was still out cold. There was a red welt forming on the back of his head from were he hit his head.

"He still has a pulse!" Hazel shouted, seeing Leo looking at Percy. The ship landed. The wind was still roaring but less. Leo went back over to Annabeth.

"Should we leave the ship and find somewhere to stay or stay on the ship?" He asked. A hissing noise came from the bushes. More from the trees. Coming from everywhere.

"Let's leave," Annabeth decided.

Piper and Annabeth helped Percy and Jason. Percy still wasn't completely conscious. Jason looked better but still needed help standing up. They came across a house in a clearing in the woods. It was early morning now. The seven went over to the house and went inside. It was a gift shop. Frank walked over to a fish monkey hybrid.

"This is fake. You can tell where the fish head is glued to the monkey," Frank stated.

A man with a fez and an eyepatch walked over to the seven. "Welcome, one and all to the Mystery Shack! I'm Stan Pines, Man of Mystery!"

The one eye reminded Leo of Bill. He shuddered.

"Hello, sir!" Annabeth said sweetly. "We need to stay somewhere for a while. We were lost in the woods and we have nowhere to go." Stan took off his eyepatch. He narrowed his eyes.

"Alright, but any funny business and you're all out, you hear? Go through that door!" Stan said, pointing to a door with 'Employees Only' on it. The seven pushed through the door. On the other side, two people were arguing. They looked like twins. The arguing stopped abruptly when one of them spotted the teens. The boy looked at them suspiciously.

"Who are y-" He started. The girl cut him off. "Hello, I'm Mabel! That's Dipper! Who are you?" she said smiling. The six were silent for a moment. Percy was silent because he had fallen back unconscious. Annabeth was struggling to carry him now. Jason was okay to walk on his own now.

"Can I put him on the couch?" Annabeth asked the twins, gesturing towards Percy.

"Sure but how is he unconscious?" the boy, Dipper, said.

"He banged his head," Jason said weakly. Dipper rolled his eyes.

"I know that but how?" he pressed.

"Umm... Annabeth?" Jason said, turning towards her.

"We got lost in the woods. These weird gnome things attacked us and they hit him over the head. They were small and we eventually fought them off," Annabeth said, hoping it made sense. The twins looked at each other. Dipper pulled a book out of his vest.

"Did they look like this?" Dipper showed a page in the book to Annabeth.

"Yes, they did," Annabeth said, relieved they didn't think they were crazy. Best they tell a lie then the truth.

"You're lying," Dipper said.

"What are you talking about?" Annabeth asked, shocked.

"When these gnomes attack, they form a huge gnome! Now, tell us the truth!" Dipper said triumphantly.

Leo was watching the exchange with interest.

Annabeth sighed. "We're..." she looked at the others. They nodded their head, except Percy. "... demigods."