Vol. 1 : Motoyan Papa to Hitsuji-sensei
Hitsuji, an elementary school teacher, seemed to have destiny on his side when an unknown acquaintance, Hatoyama Keiichi, and his child come late to school only to find out the past they share together...

Vol. 2 : Motoyan Papa to Hitsuji-sensei Hidamari
Compilation of Haru-hen (volume exclusive) + standalone extra chapters.

Vol. 3+ : Motoyan Papa to Hitsuji-sensei Yotsuba
"How can I be with you more?" - Hitsuji, an elementary school teacher who is no longer in charge of his boyfriend Hatoyama's child, Hinata. Hitsuji laughs at Hatoyama, who is worried that Hinata will be out of his homeroom. However, while looking at Hinata, who is not very fond of his new teacher, Samejima, Hitsuji also becomes anxious...