Yn is Branch's younger sister

Yn is Branch's younger sister. She wasn't in Brozone because she was to young. She didn't leave like the rest of Branch's siblings did. She didn't fight the burgens with the rest of the trolls in the first trolls movie and she always stays in Branch's bunker. She lost all of her colors from the Rock takeover, but didn't get them back. What happens when her and Branch's brothers show up?