Kotone invites the girls to swim at her family mansion's pool, where they meet Kotone's little sister Shinobu, who seems determined to have Kotone return home. Shinobu challenges Shizuku to a swimming contest to decide who Kotone should stay with, which Shizuku ends up winning thanks to some meddling by the family maid. Later, Yuu decides she wants her own scarf, only to find the one she had her eye on had been bought by Shizuku, so Haruka goes shopping with her. They find the scarf Yuu wanted, only for her to choose a different one instead.
