Fourteen years ago, Tsubaki divorced her husband, with Tsubaki taking custody of their elder son and the husband taking the younger. Over time, the elder son moved out after finding a job, and in his place, the younger son returned to live with Tsubaki. Having grown up under a strict father, her younger son was fiercely independent and kept emotional distance, refusing to depend on her. Wanting desperately to feel some affection from him, Tsubaki invited him on a hot spring trip during a long holiday break. However, the inn they stayed at held dark, painful memories for Tsubaki—a place tied to a tragic past...