After 2 years staying at their home town for summer, Dipper and Mable Pines(16) decide to go back to Gravity Falls for the summer. They stay where they always can call home: The mystery Shack. while being there, Dipper in counters a yellow triangle. The triangle is happy to see Dipper and Mable(mostly Dipper) As the summer goes on, Dipper spends more time with the triangle. Little did they know, they both end up......