Ayumu Tamari, a high school student, battles Crystallization Syndrome—a rare disorder that transforms parts of his body into crystal during bouts of stress, anxiety, or depression. This physical embodiment of emotional distress isolates him socially as communication with peers becomes impossible, while recurring episodes disrupt his academics, forcing him to repeat a year.

Complicating his turmoil are unrequited feelings for his homeroom teacher, Kouya Onihara, a crystal researcher fascinated by Ayumu’s condition. Though initially rejecting Ayumu to avoid crossing ethical boundaries, Onihara exhibits possessive tendencies, growing jealous as Ayumu forges new friendships. These encounters fuel a vicious cycle where anxiety triggers crystallization, which deepens his distress.

Seeking solace, Ayumu crafts a new persona to navigate social encounters, yet this mask clashes with his true identity. His faltering efforts to connect with others and control his condition yield tentative strides toward resilience, even as challenges persist. Onihara eventually adopts restraint, pledging to await Ayumu’s graduation before revisiting their connection—a fragile truce in their strained dance.

Ayumu’s blonde hair, brown eyes, and shy demeanor mirror his timidity, accentuated by distinctive hair antennae. His journey underscores a struggle between self-acceptance and societal pressures, where vulnerability and metamorphosis collide.