Nozomi Momijidani is a ten-year-old fifth grader at Shiromidai Elementary School and one of the three main heroines of the story. She lives at the Little Wings orphanage alongside her close friends Sora Kaneshiro and Jun Goto. Nozomi serves as the bassist for the elementary school band Lien de Famille, a role she takes seriously. She is often the one who takes charge of the group, addressing her bandmates as "little sisters" and acting as their de facto leader.

Nozomi possesses a strong-willed and determined personality, but beneath her bold exterior she is delicate, honest, and emotionally sensitive. She cares deeply about her friends and her music, and her principal motivation is to succeed as a performer with her band. Her resolve is tested when her grandfather appears and wishes to adopt her, intending to take her to England. This creates a personal conflict, as Nozomi must decide whether to leave the orphanage and her friends behind or stay with the family she has built at Little Wings. Throughout this arc, she struggles with her feelings of attachment and the desire to honor her grandfather's wishes, ultimately choosing to remain with her band and her found family.

Nozomi's relationship with the other band members is central to her character. She shares a particularly close bond with Sora and Jun, and the three support one another both musically and emotionally. Her dynamic with the protagonist, Kyō Nukui, begins with her reaching out to him for help with a performance and gradually evolves into mutual respect and collaboration. Nozomi's notable abilities include her skill on the bass guitar and her natural leadership within the group, steering the band through rehearsals and performances with a mix of enthusiasm and earnestness.