Ten years ago, Chisato divorced her husband and raised her son, Hiroaki, alone. Determined to spare him hardship as part of a single-parent household, Chisato worked tirelessly to support and raise her child. Since childhood, Hiroaki had sensitive skin, and Chisato always cared for him by applying hand cream. After graduating high school, Hiroaki chose to work at a bakery instead of pursuing higher education—his way of easing his mother's burden. Saving money, Hiroaki invited Chisato on a hot spring trip, hoping she could relax and recover from her daily fatigue. The trip coincided with Chisato's birthday. Hiroaki had prepared a special gift for her...