Haruna is a lively tomboy in the 5th year at elementary school. One day, while playing with Hiroyuki, a boy whom she has known for a long time, they play a game of putting their private parts together. A sex education lesson given by a new teacher, Yagi, makes Haruna suspect that she might be pregnant.
| Actor | Role |
|---|---|
| HHaruna AmariHaruna Mochida | Haruna Mochida |
 Kumiko AsoTeacher Yagi | Teacher Yagi |
 Yoshiko MiyazakiHaruna's mother | Haruna's mother |
 Mitsuki TanimuraHaruna's older sister | Haruna's older sister |
 Reiko KusamuraHaruna's grandmother | Haruna's grandmother |
 Satoru SaitoHaruna's father | Haruna's father |
 Hyōe EnokiHaruna's grandfather | Haruna's grandfather |
 Toshiyuki KitamiMitsuo's father | Mitsuo's father |
 Motoki FukamiMr. Kobayashi | Mr. Kobayashi |
 Risako ItoMika Yoshida | Mika Yoshida |
| YYūya KawamuraHiroyuki Tsurumaki | Hiroyuki Tsurumaki |
| AAyaka OkumaMayu Asakura | Mayu Asakura |
| RRyota ObiganeMitsuo Namatame | Mitsuo Namatame |
| HHitomi SutoTama Maruyama | Tama Maruyama |
| YYunosuke TakemoriDaigo Kawakami | Daigo Kawakami |
| KKiyotaka YamadaMansaku Kuboda | Mansaku Kuboda |
 Satoko AbeHiroyuki's mother | Hiroyuki's mother |
 Katsuki MoriTomoko | Tomoko |
 Tasuku EmotoTomoko's man | Tomoko's man |
 Juri UenoMama of Snack | Mama of Snack |
 Ken MitsuishiHiroyuki's father | Hiroyuki's father |
 Sansei ShiomiKyoto Takamatsu | Kyoto Takamatsu |