In the wake of their mother's death, the twelve princesses were trapped in mourning for a year, which meant they couldn't do the one thing that would lift their spirits: dance. Because of this unfortunate situation, the girls sought a place to dance.
The event that allowed the plot to be sent into action was the moment Azalea met with her mother (the queen), who gave Azalea her handkerchief and made her promise to take care of her eleven sisters. The queen died soon after.
Azalea used her mother's handkerchief by rubbing it against the initial-marked brick to open a secret passage in the princesses' fireplace, which led to a place that they could dance.
Azalea realizes that Keeper has been holding back information about himself that makes her wonder if they really should free him. She also finds out that he is keeping something important of her's.
Keeper finds his way out of the secret pavilion and wreaks havoc through the castle. He fills everything with bad magic and plots to fulfill his blood oath.
Clover, Bramble, and Azalea find love as the shock and horror of the recent events dies down. Azalea's love proposes with a handkerchief (It's actually really sweet in correlation with the events of their relationship.)