The next day occurs in the chapter, revealing that Soos is letting Dipper and Mabel throw a party in the Mystery Shack.

"Hey Dipper, why are we throwing a party?''Mabel asks in confusion as she glances at Dipper.

"Bill can possess anything or anyone Mabel, so we're throwing a party to see if we can catch him," Dipper replies sighing as he explains this to Mabel.

"Oh right, how are we going to know if Bill is possessing them, though?" Mabel asks, pointing this out as she glances at Dipper.

"They will have yellow eyes, Mabel," Dipper replies sighing in frustration as he glances at Mabel.

"Oh right," Mabel says, sighing as she glances at Dipper.

"We will just have to keep our eyes open,'' Dipper says, sighing as he glances at Mabel.

"Alright, Dipper," Mabel says, sighing as she glances at Dipper.

So, with that, the party begins, and Dipper and Mabel keep their eyes open for Bill Cipher.

All of a sudden, the scene transitions over to Cathy and her mother arriving at the Mystery Shack.

"Do we really have to attend the party?" Cathy asks sighing as she glances at her mother.

"Cathy you know I have to go to work," Cathy's mother replies sighing as she glances at Cathy.

"Can't you just skip one day of work?" Cathy asks pleading as she glances at her mother.

"Cathy you know I need this job, so no, I can't miss one day of work," Cathy's mother replies sighing in frustration as she glances at Cathy.

"I know, but," Cathy begins as she glances at her mother.

"That's enough Cathy, end of, discussion," Cathy's mother says, sighing as she glances at Cathy.

So, with that, Cathy's mother goes into the Mystery Shack with Cathy following behind her.

"I'm going to help Soos with the party, so hang out with Dipper and Mabel or something," Cathy's mother says sighing in frustration as she glances at Cathy.

Cathy nods, agreeing with her mother, and with that, Cathy's Mother leaves to help Soos with the party.

"I hate it when she doesn't listen to me," Cathy says, sighing in frustration as she searches for Dipper and Mabel.

"Hey Dipper, and Mabel," Cathy says, sighing as she glances at Dipper and Mabel.

"Hey Cathy, thanks, for coming," Mabel says, smiling as she glances at Cathy.

"It's not like I had a choice, my mother works here," Cathy says, sighing in frustration as she glances at Dipper and Mabel.

"What's wrong with hanging out at the Mystery Shack?" Dipper asks suspiciously as he glances at Cathy.

"It's not like that, it's just my mother doesn't listen to me, and sometimes it's like she doesn't want anything to do with me," Cathy replies sighing in frustration as she glances at Dipper and Mabel.

"We understand, and we know what you mean Cathy," Dipper says, smiling as he glances at Cathy.

"You do," Cathy says in confusion as she glances at Dipper and Mabel.

"Yeah, when we were sent to Gravity Falls last summer, we assumed it was because our parents wanted a break from us," Mabel replies, chuckling as she glances at Cathy.

"I mean I know that Mabel and I can be a handful sometimes, so I don't blame them," Dipper says chuckling as he glances at Cathy.

"Huh, I guess we have something in common," Cathy says, smiling as she glances at Dipper and Mabel.

"I guess we do," Dipper says smiling as he glances at Cathy.

"So you, guys want to hang out?" Cathy asks, smiling as she glances at Dipper and Mabel.

"Um sure, but we have to keep an eye out for Bill," Dipper replies as he glances around the room nervously while he glances at Cathy.

Mabel nods, agreeing with Dipper, and with that, they head up to the attic.

"So, why don't you tell us about yourself, Cathy?" Mabel asks smiling as she glances at Cathy.

"Well, I was born in Montana, I live with my mother, and my father left me when I was young," Cathy replies, smiling as she glances at Dipper and Mabel.

"Oh, sorry about your father, Cathy," Dipper says sighing as he glances at Cathy.

"It's fine, you didn't know," Cathy says, sighing sadly as she glances at Dipper and Mabel.

"Do you know much about your father?" Mabel asks curiously as she glances at Cathy.

"Not really, I have asked my mom about him, but all she's told me is that he's a trickster," Cathy replies sighing as she glances at Dipper and Mabel.

"Well, we can help you investigate if you want, Dipper and I are good at solving mysteries," Mabel says smiling as she glances at Cathy.

"Thanks, but I don't have much to go on anyway," Cathy says sighing as she glances at Dipper and Mabel.

"Well, it was nice hanging out with you, but we need to get back to looking for Bill," Dipper says sighing as he glances at Cathy.

"Alright, I'll see you around I guess," Cathy says, smiling as she glances at Dipper.

Later, on that evening, Cathy goes home and Bill appears to her.

"Oh, Cathy has a crush!" Bill says, chuckling as he glances as he glances at Cathy.

"I do not," Cathy says angrily as she glances at Bill.

"Yes, you do, you have a crush on Pine Tree," Bill says, chuckling as he glances at Cathy.

"So now you decide to bother me, why didn't you bother me during the party?" Cathy asks angrily as she glares at Bill.

"I would have, but there's a magic barrier preventing me from entering the Mystery Shack" Bill replies sighting in frustration as he glances at Cathy.

"Cathy, who are you talking to?" Cathy's mother asks as she goes to see who Cathy is talking to.

"No one mom, I'm just talking, to myself," Cathy replies sighing as she glances at her mother.

"Oh, well, dinner is almost ready," Cathy's mother says, smiling as she goes to finish dinner.

"Ugh, I hate lying to her," Cathy says sighing in frustration as she glances at Bill.

"You kind of have no choice Cathy," Bill says chuckling as he glances at Cathy.

"I know," Cathy says sighing as she glances at Bill.

So, with that, Cathy eats dinner with her mother.

"Hey mom," Cathy says nervously as she glances at her mother.

"What is it, Cathy?" Cathy's mother asks curiously as she glances at Cathy.

"I was wondering if you could tell me more about my father," Cathy replies nervously as she glances at her mother.

To be continued!