Yamataro Mugihara lives as if she’s a failed equation—dreams lost, family dead, and a corrosive guilt she believes she deserves for her grandmother’s murder. Convinced she poisons every life she touches, she buries herself in soul-numbing office work and alcohol, mistaking endurance for atonement.

Her only refuge is Akio Hukitaske’s quiet pharmacy, a space shaped by his own recovery. Akio offers no pity. Instead, he meets her despair with clinical empathy, framing her chaos through chemistry, logic, and careful observation. Their conversations form a fragile bridge between two broken minds.

When Akio’s unconditional kindness pierces Yamataro’s self-loathing, it detonates into an argument that shatters their bond. The fallout triggers a brutal, unsanctioned intervention by Raka, a fearsome old granny who drags Yamataro into Tokyo’s chemical underworld. The near-fatal ordeal forces Yamataro to confront a truth she’s avoided: she deserves to survive.