Moshimo, Japan. The annual fireworks festival is about to take place and a group of schoolboys, arguing over whether they are round or flat when viewed from different angles, set out to find it out.
広瀬すず
as Nazuna Oikawa (voice)
菅田将暉
as Norimichi Shimada (voice)
宮野真守
as Yūsuke Azumi (voice)
浅沼晋太郎
as Jun'ichi (voice)
豊永利行
as Kazuhiro (voice)
梶裕貴
as Minoru (voice)
三木眞一郎
as Nazuna's Mother's Fiancé (voice)
花澤香菜
as Teacher Miura (voice)
櫻井孝宏
as Teacher Mitsuishi (voice)
根谷美智子
as Norimichi's Mother (voice)
飛田展男
as Norimichi's Father (voice)
宮本充
as Yūsuke's Father (voice)