In the episode,"The Werewolf Spell," Hanna is attacked by a dog, which was given werewolf-like qualities by villain Zanrelot. Later at night, Hanna sent her daughter, Milli, off to bed, and quickly noticed some hair covering the bitemark on her leg. Hanna turned heel and transformed into a werewolf under the full moon, and she prowled in the darkness; hovering around a flock of sheep before devouring one of them. The Guardians noticed Hanna acting strangely the following morning, as she is also shown with leaves in her hair. Later that night, the evil Hanna transformed into a werewolf once again and devoured another sheep. Hanna returned home and entered to her bedroom, and it was there that Milli opened the door and witnessed Hanna's villainous transformation, as Hanna continuously snarled while she was laying asleep.
The Guardians learned about the werewolf curse and teamed up to save Hanna, as the third night could end up with Hanna being a werewolf forever. Hanna turned heel once again on the following night, and she went after the group following her latest transformation. The group fired their water cannons at Hanna to subdue her temporarily, but the villainess continued her attempt to attack the group, which prompted Milli to attempt to get through to her mother. Her attempt was successful, as Hanna's love combated against the werewolf curse, and she was freed from the curse for good.