After learning that her mother will not be home for her birthday, Hinako moves into Sana's apartment. Hinako's inexpertness in cooking and Sana's shock at her arrival contributes to the hectic situation, but Sana manages to get her comfortably situated into the room. She was not able to sleep without her Yeti giant soft toy and asks Sana to be her Yeti and let her hug him. Sana eventually learns that the day was Hinako's birthday, and the following day, takes her around town with Syusuke. Once they return to Sana's apartment, Nanaka, Aoi, and Syuri have prepared a birthday party for Hinako. After Hinako leaves the party, she thanks Sana for the only birthday party she has ever had with a kiss on the cheek before running home.
ある日、突然、佐菜のアパートに雛子が転がり込んできた。聞いてみると、なんと、家出をしてきたのだという。佐菜が困惑するのをよそに、我が物顔で振る舞う雛子。最初は迷惑に感じていた佐菜だが、ふとしたことで雛子の家出の理由を知ると、ある計画を実行することに…。
