Los hermanos mellizos Dipper y Mabel Pines tienen una aventura inesperada cuando pasan el verano ayudando a su tío abuelo Stan a atravesar una trampa turística en la misteriosa ciudad de Gravity Falls, Oregon.

Marianne is in bed after falling from her horse. She occupies herself by doodling in a sketch book, drawing a boy inside a bare house. When Marianne falls asleep, she finds herself outside the very house that she drew.