S1·E9 A Green Heart Present

Akira, the sci-fi fan in Chocolat and Vanilla's class (who believes them to be extraterrestrials after witnessing them falling from the Moon) is on sick leave, and Chocolat is asked to deliver a note to him. However, they realize his sickness was a pretense as he was searching for Hirotsu, his dog, who has disappeared. Chocolat organises a search party, but fails to find it. Later Hiroshi is found waiting for a ferry bearing Akira's dad.