The gentle sound of waves creates a soothing rhythm, stretching out across the shimmering seaside. A woman's figure plays joyfully along the shoreline. Mother Shinobu and her son Yasuhito have come alone for their annual family trip, as her husband is unable to attend due to work. With her husband absent, Yasuhito, though slightly nervous, begins to focus on spending time with his mother. In truth, he has been in love with Shinobu ever since learning she had remarried. Growing closer to his mother by the sea, they share a bath together at the inn where they're staying. Overcome by his uncontrollable feelings, Yasuhito heads to Shinobu's room that night.