Ai's mother died before the story begins, deeply shaping Ai's life and choices. Following her mother's death, Ai moved to Tokyo alone, driven by her promise to become a singer. This promise anchored all her actions and dreams. Her mother's absence and the weight of their vow forged Ai's determination to reach her musical goals against all odds. The narrative presents her mother as a fundamental force, felt through Ai's memories and the lasting impact of their bond.