Rewrite of my old Monster Falls fanfic. WITH AN ACTUAL PLOT! WOW!

One fateful morning, Mabel and Dipper fall into the bottomless pit again. But this time, they don't come out in exactly the same place they started in...

Three years after their first summer in Gravity Falls, Mabel and Dipper are back after their parents let them choose to go to high school there. But while Dipper is busy still trying to cope with life as a girl, she and Mabel fail to notice that not everything at Gravity Falls High is as it seems... ~A Sequel to Change of Identity~

One day in the forest, Mabel is mysteriously saved from the gnomes by an unknown person. And, being Mabel, she wants to give them a thank you gift. But when she finds the one who rescued her, it's not who she'd expect. At all.