Wendy went down to the gift shop, because she thought nobody would be there. She felt awful. Even though Dipper was only twelve, she felt as if she had ruined a huge part of his life. She didn't want Dipper to be angry at her, or for him to hold onto the fact that the journal was gone. After all, they could still go on adventures; it would just be difficult since that journal gave them a lot of clues. Whatever the case, Wendy couldn't help to feel like this was her fault. She really wanted to be alone, but Soos was sweeping. "Hey, dude, you okay?" he asked. "You look like someone got hit by a truck."
Wendy shrugged. "It's about as bad." She explained to Soos the short version of what happened. While talking, Mabel arrived back from her sleepover, so Wendy filled her in.
Mabel and Soos did a pretty good job of making Wendy feel better, actually. Mabel said she should just leave Dipper alone (which she really didn't want to do), saying that he'd get over it. Both of them were disappointed that the journal was destroyed, though.
Wendy left out the crucial detail of them finding the portal, and Stan being the one to operate it. She knew Stan would never want her to know, and since she did, the best thing she could do was keep it a secret.
Stan came into the room in the middle of the conversation, probably to tell everyone to get to work (which really would have been unethical for Wendy; she was in her pajamas still). Wendy didn't let him speak though. She paused mid-sentence and said, "Stan! I need to talk to you. Right now!" Before he could protest, she pushed him into the living room.
"Wendy, what do you want?"
"Stan, please, before you say anything, hear me out. Please." Wendy went ahead and confessed everything that happened to Stan, from the first dream she had up until just minutes ago, when she told Dipper about the journal.
Stan looked horrified at the end of the story. After yelling at her for at least ten minutes about how reckless that was and how much danger she had put Dipper and herself in, Stan sighed. "Just... How did you guys... Oh, God..." Stan rubbed his forehead, like he had a headache. "You've really done it this time, Corduroy."
"Well, I didn't want Bill to throw your great-nephew into the portal! That would have been worse."
"You don't even know the half of it," Stan told her. "Hey, now that you know about this, you cannot tell a soul."
"I haven't," Wendy said. "I wasn't planning to. Ever."
"Good," Stan said. "And as for Dipper..." He looked Wendy in the eyes, showing sincerity. "I have something that might fix things, but I have to go back down to the portal. Just go along with what I say. Okay, out." Stan pushed Wendy through the door and into the gift shop.
"Okay, employees. Wendy here has convinced me to throw another party at the Shack. She says it's good to have a "hip image" with the young people, whatever that means. And I can make lots of money, so it all works out! I need you all to go outside and make signs for the party. Now, or you're fired!"
Soos, Mabel, and Wendy all shuffled outside. As they did, Wendy turned back and gave Stan a smile to express her gratitude.