The story takes place after Rapunzel and Flynn Riders wedding. But then out of the blue Mother gothel returns from the tower which she (quote and quote) "disappeared" from and the first thing that pops into her mind when she returns is that she wants revenge on Flynn Rider for cutting off Rapunzel's hair and taking away her unity. So this story is mainly about what happens after Rapunzel and Flynn Riders wedding, How mother gothel survived that very and I do mean very high fall (push) out the door/window, and what happens when a unexpected twist takes place and there may not be a happily ever after.
4 parts