It's been three years since their last summer in Gravity Falls. Dipper and Mabel, now High-School Seniors, return for the Christmastime wedding of Soos and Melody. They reunite with several old friends as well as their Great Uncles. However Blendin arrives to ask for their help. A new villain from the future has arrived in order to discover a powerful hidden relic created in wake of Bill Cipher's destruction. When this new villain steals Ford's journals, Dipper and Mabel must write their own, all the while trying to determine what the future holds for both of them.
