Cheri is an eleven or twelve-year-old human girl with long blonde hair and blue eyes, residing with her parents in a village. She harbors deep longing for her older brother Toby, who departed years earlier after clashing with their father. Toby unexpectedly returns, now an apprentice to the formidable magician Lord Kuruku and wielding magical abilities. His mission involves transforming humans and animals into mindless, zombie-like "Living Puppets" for Kuruku’s designs.  
Initially overjoyed at Toby’s return, Cheri’s joy turns to fear when she witnesses his icy demeanor and unsettling powers. Her terror peaks after Toby transforms their parents and the entire village into Living Puppets overnight. Alone and devastated, she vows to find her brother and halt Kuruku’s scheme to restore everyone. This resolve fuels her journey.  
While questing, Cheri meets Unico, a young unicorn. They ally and travel together to confront Kuruku, braving hostile creatures and the magician’s minions. Cheri displays courage and compassion throughout, notably when comforting demon children weeping over their own cursed parents.  
Her dedication to saving her family never wavers, even when Kuruku directly threatens her. He briefly transforms her into a Living Puppet during her plea for Toby’s redemption, though Unico rescues her. Later, Toby shields Cheri from Kuruku’s attack, becoming a puppet himself—an act rekindling her belief in his inherent goodness.  
In the climax, Cheri aids Unico’s battle against Kuruku. After Kuruku’s defeat reduces him to an inanimate puppet, Cheri keeps him as a toy, embodying forgiveness and a wish for companionship. All transformed beings, including her parents and Toby, revert to normal. Cheri shares a farewell with Unico before the West Wind spirits him away, concluding her story with her family reunited and her home restored.  
Early concept material titled *Unico and the Kingdom of the Sun* featured a similar character named Chieri, who sought aid from the Sphinx and Queen Urania following her brother’s betrayal and competed in a dance contest to reach the queen. These aspects were omitted from the final film.