A 100-year-old resident of a Lake Biwa nursing home dies mysteriously. Did a respirator keeping him alive suddenly malfunction, or was he murdered? A young detective on the case meets a female caregiver. The investigation runs into a dead end, but the two fall into a passionate but forbidden relationship. Terrifying memories emerge from the vast, deep lake to ensnare the detectives on the case, the caregivers, and a reporter trying to uncover a hidden past.