Aika, a college student who has returned home during summer vacation, is delighted to see Haruna, Yankee, and Nana. All four grow up in families where premarital sex is prohibited. Four childhood friends with no sexual experience spend the summer trying to lose their virginity. Haruhi Oguri, the female director who was the first to challenge the pink film, vividly reflects the sexuality and life of women with different complexes and habits, and this work of her was highly praised.

Narumi, who has an aggressive personality, stabbed her colleague and went to prison. After serving her time, Narumi is released and goes back to her hometown where she grew up. Narumi goes to her younger brother Kei's home. At a young age, their parents died in a accident and Kei is the only one left Narumi can rely on. After Narumi sees Kei and his girlfriend Kana living together happily, Narumi decides to take her brother back. Narumi reveals a secret between her and Kei.