It has been 10 years since twin siblings Dipper and Mabel Pines had last visited Gravity Falls. 10 years since they had seen their Grunkle Stan and Ford, Soos and the rest of their friends. 10 years since they had their most amazing summer adventure yet.

But at that time, they had only been 12 years old. Now they were 22 and they each had different occupations after they graduated college. Dipper was now working on his own television show about ghost hunting show called Dipper's Guide to Ghost Hunting while Mabel was on a contract deal with a big fashion industry on making cute and fashionably sweaters for people after getting a college degree in design making. She loved making sweaters and wore different ones all the time! She couldn't wait to share her amazing talent with the rest of the world and get to see them in her sweaters! It was going to be amazing!

Great things were happening to the rest of the characters too. Stan and Ford were still on their boat adventure, exploring creatures on the sea and having a blast. Soos was running the Mystery Shack with his newly wedded wife, Melody and was soon expecting a baby with her. Fiddleford McGucket was making well-made inventions for the gov. Pacifica was offered a job to be a model. Gideon was still trying hard to be a good person and Candy and Grenda constantly visited each other, talking about their excited lives. Grenda excitedly raved about her boyfriend's Marius proposal to her while Candy talked about her latest book.

Things were going well with the rest of the townsfolk too.

Yup. Since the defeat of the evil triangle demon, Bill Cipher 10 years ago, everything was going perfect, just perfect in Gravity Falls.

Until one day….

Out on the sea, the Stan twins were stargazing, looking up at the different constellations at the sky with Ford recording them in his notebook.

"Ah, nothing like ending a day at the sea than by gazing up at the stars, eh, Poindexter?" Stan laughed, playfully nudging his brother in the arm, while taking a sip of his Pitt Cola.

Ford chuckled. "Yes, Stanley. This is very relaxing. Reminds me of when we stargazed as kids back when we went camping at Glass Shard Beach 40 years ago."

Ford gazed up at the constellations and continued recording them in his notebook while Stan smiled and happily glanced at the star-painted sky.

Suddenly without any warning at all, Stan gasped, grabbed his head and fell on the sand, his back turned to Ford. "Ford! Ford! Help me!"

Ford turned to Stanley, his eyes widened in horror. He dropped his notebook and rushed towards his brother in alarm. "Stanley!" He cried. "Stanley! Are you alright?! What's going on?! Are you hurt?!"

"I-I-My head!" Stan bellowed.

"What about it?!"

"IT- IT-" Suddenly Stan paused and stood still, his back still turned to Ford.

Ford looked at his brother in concern. "Stanley?"

Stan didn't answer.

"Stanley! Answer me!" Ford pleaded. He placed a six-fingered hand on his brother's shoulder sympathetically. "What's wrong with your head?"

When Stan turned to face him, Ford gasped. His brother's eyes were not his eyes. They were yellow. Ford had only seen those eyes on one being.

"No…." Ford started to panic. "No! It can not be!..."

"HEY SIXER!" The possessed Stan laughed. He gave Ford a hard push. "I'M BACK!"

Ford stared in horror. He didn't know how it was possible, but he saw it with his own eyes in front of his possessed brother. It was Bill Cipher in his brother's body and he was back.