Hikari Mizutsuki belongs to a family deeply immersed in the performing arts. Her parents run a small theater in Asakusa, where she shines as its signboard star, acclaimed for her expertise in review shows. She shares her life with kind parents, a younger brother, and a sister, united by their admiration for the fleeting beauty of fireflies. Despite receiving invitations from larger theaters, Hikari consistently declines these offers, prioritizing her unwavering loyalty and dedication to her family's theater and its devoted audience.

Within the Utahime Dream project, Hikari functions as one of several interconnected characters, integrated into a collective performing unit. This group releases music, including singles like "Haru Yo Koi," "Syanikusai," "Ame No Planetarium," "Nanpasen," "Ruriiro No Chikyu," "Hungry Spider," and "Hotaru," anchoring her participation in the project's musical endeavors alongside fellow performers.