Sonno by haruki murakami

A married woman inexplicably stops sleeping and, instead of collapsing from fatigue, experiences a startling clarity and prolonged wakefulness that loosens her routines and social ties. Her secret nights—spent reading, wandering, and quietly examining her feelings—reveal hidden currents in her marriage and in herself, turning ordinary domestic life into something eerie, intimate, and disorienting as she confronts desire, identity, and the fragile boundary between wakefulness and sleep.