Summer vacation is here. Twin brother and sister Mabel (voiced by Kristen Schaal) and Dipper (voiced by Jason Ritter) are driven by their parents to a remote town called Gravity Springs for summer vacation. Here, their uncle Stan runs a tourist attraction called "Mystery Shack" that specializes in blackmailing tourists. There are all kinds of strange things in it. However, what makes people feel more creepy is the forest in this weird town. Dipper, who is cautious and smart, noticed the strangeness of the forest, and then found a mysterious notebook buried underground, which records the unknown secrets of the mysterious town. The optimistic Mabel and the witty Dipper met Wendy and Sus, the clerks of the mysterious hut, and met various wonderful town residents. In the weird town of Gravity Springs, they experienced a series of strange events, dwarves, lake monsters, wax figures, psychics, and their summer vacation is destined to be extraordinary.