Summer Clark is a newcomer to Gravity Falls, Oregon. Her parents sent her here, so she could be safe, when really she's in even more danger. When she arrived everyone was as frightened as they were 30 years ago. When a demon took over the town. One day while Summer is in the forest, she finds an abandoned tourist trap that was called, The Mystery Shack. There she finds out Gravity Falls dark past, and meets the reason for the past.