When two twelve year old twins, Dipper, a bright kid who is obsessed with the paranormal and discovering mysteries. Mabel, a funny kid who is obsessed with boy bands and falling in love with boys. are sent to spend the summer with their great-uncle, Grunkle Stan, in the mysterious town of Gravity Falls, Ore. Grunkle Stan has the kids help him run The Mystery Shack, the tourist trap that he owns. The twins try to adapt to the weird surroundings but sense there is something strange about Gravity Falls and begin to unlock its secrets. When Dipper uncovers a cryptic journal that offers insight into the town's mysteries, he and Mabel use it and their enthusiastic desire to vanquish evil to battle the imminent mysteries that surround them With Wendy Corduroy, Mystery Shack cashier; Soos Ramirez, a friend of Dipper and Mabel and handyman to Grunkle Stan; plus an assortment of other characters, Dipper and Mabel always have an intriguing day to look forward to.

Note: Alternative universe where Dipper and Mabel are twin vampires. They looked a lot like the other but Mabel has a cute innocent look, with long pink hair and bright green eyes, while Dipper has a more proud mature sexy look with had long silver hair and red eyes.