Twin siblings Dipper and Mabel Pines continue their summer in Gravity Falls, Oregon, where their great-uncle Stan runs the Mystery Shack, a tourist trap surrounded by strange secrets. As Dipper, Mabel, Soos, and Wendy search for the unknown author of the mysterious journals, Stan works to operate a hidden portal beneath the shack, and the group faces the growing threat of Bill Cipher, a dream demon with plans to take over the world.