White Christmas

S1, E3: Brothers Aki and Shima are upset by the sudden appearance of a "fourth brother" in the Kaidou family, and Haru's excessively affectionate attitude towards Ren makes Aki explode with rage. Meanwhile, Haru happens to witness a car accident in the city. Since then, Haru begins leaving Ren alone in the apartment. On top of that, while Ren is home alone, one of Haru's customers from the host club forces her way into the apartment, and--?!