It starts off at Morning time. Dipper rose turn around in his bed staring at Mabel's filthy side of the room.
"Man, how can she sleep like that?" Dipper had affirmed. Dipper got out of bed and walked down to the kitchen where Mabel is eating a large bowl of cereal.
"Morning Dipper, how'd you sleep?" Said Mabel. Dipper grabbed the box of cereal and milk and poured it into his bowl. "Mabel, you really need to clean your side of the room." Dipper remarked.
"But it's my room too." Mabel replied.
"I know, but, the smell is awful." Dipper reported.
"Oh smell, smell. Hey, have you seen Grunkle Stan any where? I haven't seen him in a short while." Mabel asked.
"Yeah, he's out of town for the week. He'll be back on Monday."
"Oh, well I'm off to lay around in my own filthy side of the room."
"Okay, see ya!"
Mabel walked into the living room, and into the hallway past the vending machine. She ceased and heard a loud scream. The screaming sounded like it was coming from inside the machine. Mabel disregarded the sound and went upstairs to her room.
2 hours later.
Soos was sleeping on the counter of the store. Dipper walked in holding his Journal #3. He sat on the floor and began reading more information it has. As he turns page from page, he stopped on one interesting page. This page was about Demons.
"Demons? Sounds interesting." Dipper simpered. Dipper eyes were glued to that page for a long interval of time. He was learning more things about Demons that lived in Gravity Falls.
"'A Demon can transform itself to any living creature, including humans, I have no clue how to stop Demons, this may be my last journal entry. But if someone finds this Journal, please, please do me one last request. Trust no one.' Wow, so that's why this Journal was buried. The last owner probably didn't want anyone to find this Journal so easily. I have got to tell Mabel about this!" Dipper wailed. He ran into the hallway and heard sounds of screaming next to the Vending machine.
"What's that weird noise?" Dipper asked.
He had compressed his ear against the glass and he heard hear more cries for help.
"I have got to find a way to get in there." Dipper searched around the living room and found a golf club.
"I'm sorry Grunkle Stan..." Dipper oscillated the Golf club at the machine. Glass splintered everywhere. The machine opened up. Inside of it were stairs leading downwards. Dipper was frozen with fear.
"Mabel! Come here for a sec." Dipper yelled. Mabel came skipping down the stairs and standing towards Dipper.
"What's up, Dip?" Mabel said. Dipper pointed his fingers to the mysterious stairs.
"Whoa...cool...hey, wait a minute, you broke Grunkle Stan's vending machine, didn't you?" Mabel asked.
"Mabel, is this the best time to ask that question? Look, my Journal says that Demons can transform themselves into any living creature, including humans..."
"Okay, what are you saying?"
"I'm saying that, maybe, Grunkle Stan is a Demon."
Mabel laughed. "A Demon? Dipper, you read a lot of books. Just tone it down and come watch T.V. with me. We can watch Ducktective."
"Mabel, I want to find out what's down these stairs, are you coming with me or not?"
"Ugh, fine, I'll go."
Dipper and Mabel walked down the stairs. The area was turning red and it became really hot. Mabel was fanning herself, and Dipper took of his hat and wiped his forehead.
"Man, why is it so hot down here?" Dipper asked.
"I don't know, but I wonder what's down here..." Mabel replied.
Mabel and Dipper walked off of the stairs and walked towards a dim hallway full of bones and blood.
"Ew, what is this place?" Mabel solicited.
"I don't know, but I think this Journal might tell us something." The hallway lead to a huge room full of chains and blood everywhere. Dead bodies covered in blood were around the chains.
"You two...please...get out of here." A man's body was crawling towards Dipper and Mabel. They both screamed and ran away from it.
"Please, I am no harm to you. Just get out of here, it's not safe."
"Hey, don't I know you from somewhere?" Dipper asked.
"Yeah, I'm Old Man McGucket. Get out of here while you still can..."
"Who or what did this to you?" Mabel implored.
"It was a man who did this. I remembered that I was on the ground, my legs were gone, I couldn't see with all the blood. I looked up and saw a man in a black suit standing above me. Then I passed out, that's all I remember."
"A man in a black suit? Mabel! He must be talking about Grunkle Stan."
"Dipper, you're my brother and I will always believe you, but I just can't see Grunkle Stan doing all of this."
"What are you saying Mabel?"
"I'm saying that I'm leaving and telling Grunkle Stan that you broke the machine." As Mabel turned around to leave, a force stabs her in the stomach.
"MABEL!" Dipper yelled. He ran towards her body.
"Mabel, I won't leave you here."
"Hey, Dipper...you were right all along, Demons are real, and Grunkle Stan is one of them."
Mabel lifted up her finger and Dipper turned around. Standing before him was Grunkle Stan...his demonic form. His eyes were pure black, his fingers were covered in blood, his smile was thirsty for blood.
"Grunkle Stan..." Dipper bawled.
"Trust no one, Dipper."
An hour later, Soos and Wendy were wondering where did everybody go. They walked into the hallway and saw the vending machine...unbroken, unsplintered, and the golf club was safely back into its original place.
"Looks like no one is home." Soos said.
"I know, hey, let's go to the park and tease old people for being so old!" Wendy replied.
Mysteries are common for Gravity Falls.