Miwako once shared an intense physical bond with her son Kaoru, her only family. However, Kaoru left their hometown to work in Tokyo, and five years have passed since then. During that time, he never contacted her or returned home—plagued by repeated unemployment and deep self-loathing, he lacked the courage to face his mother. Inside Miwako, a powerful maternal love surged, an unbearable longing for Kaoru to come back to her now and stay with her forever. Eventually, Kaoru appears before her once again. To celebrate his return, Miwako invites him on a hot spring trip. As their reunion unfolds, new emotions begin to stir between them.