Mystery Twins- Gravity Falls
SpruceForest
It's been 4 years since the events of the Wierdmagedon
Mabel and Dipper haven't been back to Gravity Falls since, as the Gruncles have been out adventuring, their parents wouldn't allow them to return with no one to stay with.
Instead, they have been slowly writing their own journal of the strange creatures they find in California.
But when they return home they find a letter, telling hen they have to return to Gravity Falls for some unknown reason. And of course, the 17 year old twins can't pass up the opportunity.
DISCLAIMER: I don't own the characters they are to Disney and Alex Hirsch