After finding a strange book in the forest, Dipper begins to learn about the dark side of Gravity Falls, and suspects that Mabel's new boyfriend is a zombie.
Dipper and Mabel hear rumours that a sea monster lives at the bottom of the local lake, and enlist Soos to take them out on a boat to see if the monster really exists.
The kids discover Stan's collection of wax sculptures, and Mabel decides to create her own. But when someone sabotages it, it's up to her and Dipper to solve the case.
Dipper and Mabel meet an intriguing new neighbor: a psychotic child fraud named Li'l Gideon. When Gideon begins obsessing over Mabel and tries to win her over, Dipper tries to stop him.
Dipper brings a video game character, Rumble McSkirmish, to life so he can fight Robbie, but when things go too far Dipper realizes he needs to save Robbie. Meanwhile, Mabel tries to end Stan's fear of heights.
Dipper finds a magic crystal with the ability to grow and shrink anything, but Gideon gets his hands on it and tries to get revenge on Stan and take the Mystery Shack.
It's Summerween, and Dipper and Mabel are visited by a monster called the Summerween Trickster, who informs them they must collect 500 pieces of candy, or be eaten.
Mabel is in charge of the Mystery Shack after making a bet with Stan to see who can the most money in three days, and determine which of them is the better boss.
Dipper wants his own room and when Soos finds one in the shack, Stan makes Dipper and Mabel compete for it. Meanwhile, Dipper has found out that the shag rug inside lets you switch bodies with whomever you shock.
When Mabel Discovers that her favourite boy band is actually a bunch of imprisoned clones, she sets them free, only to decide on keeping them for herself; Dipper is convinced that Robbie plans to brainwash Wendy with a secret message.
