Rei Yuki divorced her husband when her son was in college and raised him alone. She managed to get him into university, but he became obsessed with club activities, neglected his studies, and eventually dropped out. After that, he joined a small theater troupe hoping to pursue a career in acting, but the group disbanded due to the pandemic. Since then, her son has lacked motivation and now works as a delivery driver to get by. Determined to break this cycle, Rei decides to invite her son on a hot spring trip.