Rieko gave birth to a child named Yuki during her time in college, only to be abandoned by the father. Choosing to raise her child as a single mother, she resolved to support her family through hard work. Though life was tough as a single-parent household, Yuki grew up well-behaved and never caused trouble. However, Rieko's long working hours and lack of rest gradually took their toll, leaving her burdened with loneliness while struggling to keep up with her job. When the chance came to use her paid vacation for a hot spring trip, Rieko hesitated, still preoccupied with work responsibilities…