Book One, Book Two, Book Three.

Each book has its own powers. With three of them together, the power is limitless.

When the power is unleashed, it will create a huge mass of destruction against Gravity Falls. Once Gravity Falls is broken, the power will consume Earth.

Without Book Four, Bill Cipher would not be able to be stopped.

Remember, without Book Four, nothing will stop them…

Stop them…

Stop them…

"Aargh!"

Dipper woke up, feeling stunned and having beads of perspiration covering his face. His face showed limitless emotions: Horror, shock and depression.

His body was shivering from the nightmare he had. Despite the cool fan blowing on him, the beads of perspiration did not go away. His eyes was very red; as red as the blood from the scar he had many years ago.

Many years passed after Dipper got hold of Book Two and Three. He also could not believe that such nightmares he had just now occurred the night before his birthday.

"Happy Birthday, Dipper!" Mabel screeched as she jumped up the stairs playfully.

Mabel was Dipper's twin sister. They're pretty much the same, except for the fact that Mabel is sillier and more childish than Dipper. Everyday, for Mabel, is a new sweater day. Right then, she was wearing a sweater with a picture of a unicorn on it.

"Mabel, don't tell me you created another party," Dipper said, smirking.

"Oh, maybe, maybe not," she replied, trying her best to hide her grin.

Dipper got out of the bed and grabbed his favourite cap, the cap that has a pine tree logo on it. He was wearing his all-time favourite shirt and jacket, with his same pair of pants. He dashed downstairs, expecting people to wish him happy birthday. But to his disappointment, there were no banners and no people there.

-:-

"I knew it!" Dipper exclaimed.

A beautiful morning breeze glided through the windows of Dipper's bedroom. Although the breeze was cooling and peaceful, it was not enough to calm down Dipper's rage. He was furious that no one remembered his birthday.

"The 13thbirthday of my life is really unlucky," he murmured under his breath.

"Don't be too disappointed, Dipper," Mabel reassured. "I remembered your birthday."

"That doesn't make a difference" Dipper said. "What about Wendy? She never forgets my birthday."

Mabel stayed silent as she thought of words that could console her brother, but to no avail. But in her heart, she knew that the party was about to start.

-:-

"Hey Grunk," Soos greeted as he walked over to the fridge and pulled it open.

"The plan is mixed up," Stan wondered out loud. "Where's Mabel?"

"Probably still bonding with Dip," Soos replied, grabbing a bottle of Mountain Dew.

"Soos, cut with the nicknames or you're fired," Stan said, glaring at him.

"Chill, Grunk," Soos said before drinking a gulp.

Stan's deadly glare continued, not daring to plop out of his chair and fire him.

-:-

Dipper watched as Mabel ran out the door with glee. He stared into space. 'Why?' was the question he kept asking himself. It seemed like hours before he suddenly heard a cry for help. His eyes were opened wide.

"Mabel!"

Dipper dashed through Soos and Stan. He slammed the door open and ran to where he heard the cry. He stopped when he saw the horrid sight of Mabel being hit repeatedly by a random person. Dipper stared in horror a few seconds before jumping onto the stranger and kicked him. The bully fell onto the ground.

"Mabel!" Dipper exclaimed.

He ran to his sister who was hurt. He slowly carried Mabel and brought her upstairs. After placing Mabel on the bed, he ran down.

"I'll get water!" Dipper shouted as he ran.

But the truth was, Mabel was not really Mabel. The "Mabel" stood up and grinned evilly.

"Oh Dipper," she said.

"Mabel" took an amulet out of her pocket. She whispered something. Suddenly, light engulfed the room. When the light died down, Mabel wasn't there. But it was someone else. Someone Dipper knew very well. The small guy with white hair. He had a blue shirt and his face looked like a pig. It was Gideon.

"Oh Dipper," Gideon repeated with a grin.

"Don't you know I am not your sister?"

-:-

Mabel skipped her way home. She had a wonderful time with her friends. She hopped into her room. She placed her gift which her friends have given her: A necklace.

She turned around to grab her bowtie before opening her eyes wide in horror. Gideon was there. He did not realise Mabel was behind him when he rummaged through Dipper's dresser.

Sometimes, Mabel's way of solving problems is not actually right. In that situation, she should've grabbed her baseball bat and slam it onto Gideon. But because of her silly characteristic, she instead did it in another way.

"Gideon! What are you doing?!" Mabel shouted.

Gideon stepped back and saw Mabel clenching her tiny fists.

"Mabel, how nice to see you," Gideon said sarcastically, having a smirk on his face.

Without a word, Mabel threw herself onto Gideon. He dodged and grabbed his amulet, whispering into it before ducking under Mabel's kick. Gideon slowly disguises himself as Mabel.

"Fair," Gideon began.

"And square," Mabel finished as she threw multiple punches at Gideon.

The fight continued non-stop. They stopped when they saw Dipper walking up the stairs with a cup of water. Dipper did not realise what was happening because he looked down onto the glass of water.

"Sorry that I was slow, Mabel. There was no water so I had to run to the river and clean the water after scooping it up," Dipper said as he looked up. His eyes opened wide.

"Am I seeing things?" Dipper wondered out loud as he saw the two Mabels fighting. "I kinda got sea water in my eyes."

The two fighters stayed silent.

"OK…" Dipper said, stepping backwards down the stairs.

Once the sight of Dipper vanished, Gideon and Mabel looked at each other and started fighting again.

"You… will… not… win!" Gideon said, whipping out a container and opened it up. Mabel slowly got sucked into it.

"No!" Mabel shouted.

Before she vanished, Mabel grabbed Gideon's shirt. Both of them staggered into the portal and vanished in thin air.

"OK, my eyes are washed," Dipper said, rubbing his eyes while walking up the stairs. When he opened his eyes, there was no one there.

"Mabel…?"