Reiko Ichinose inhabits a decaying neighborhood bordering a forest, toiling in a bar and the shadowed alleys of the "Edge of the Forest" red-light district. At fifteen, she bore her son Kai under veiled circumstances, the father’s identity shrouded in speculation, sparking relentless mockery from neighbors who denounce her as reckless and morally corrupt. Defying their scorn, she cultivates an unshakable bond with Kai, fiercely shielding him from their bleak surroundings while weathering her own struggles.

Determined to carve a brighter path for him, she brokers his relocation to the care of Sosuke Ajino, his piano teacher, swayed by the man’s earnest reverence for Kai’s artistry and indifference to her stigmatized life. This sacrifice mirrors her resolve to insulate Kai from their district’s hardships. Her unseen yearning for the sea, a distant dream etched into Kai’s name, lingers as a private testament to her quiet hopes.

Raised within the same red-light labyrinth she now navigates, Reiko persists in her despised profession, cloaked in hardened disdain for both her work and the men it serves. Whispers tie Kai’s paternity to Ben-chan, a neighborhood handyman, though no confirmation follows. Her identity orbits Kai’s survival—a mother whose grit and selfless devotion propel his opportunities, even as gossip brands her a pariah.

Kai’s vocal defiance against slurs aimed at Reiko underscores their loyalty, while her pragmatic alliance with Ajino thrives on tacit respect, the teacher’s focus fixed solely on nurturing Kai’s gifts. Her story remains anchored not in personal transformation but in the ripples of her choices, which steer Kai’s journey toward horizons she herself could never reach.