A legendary yuri work from Japan, a hot topic that aired as a TV anime in January 2018. During summer vacation, Yuzu and Mei go on a pension trip with their close friends, including Harumi and Matsuri. While enjoying a barbecue and playing card games, Yuzu savors the joy of being able to kiss Mei as a couple in secret. Meanwhile, Mei, who occasionally wears a sad expression, seems to desire Yuzu more passionately than usual for some reason. As this unfolds, Matsuri's expression darkens after overhearing a "certain conversation" between Himeko and Suzuran... A dark shadow silently approaches the sisters' love.