Kanojo, Okarishimasu

Synopsis

Chizuru runs away after she and Kazuya encounter each other. Once the coast is clear, she tells him to not say anything. The next morning, they find out they live next door at their apartment, much to Chizuru's chagrin. Later that day, Kazuya receives a call from his grandmother, telling him that she is coming over to visit. He then begs Chizuru to help him out, but she refuses. When Kazuya's grandmother comes over, she is disappointed Chizuru has not shown up. When Chizuru hears their conversation, she arrives at Kazuya's apartment. Afterwards, Chizuru agrees to be Kazuya's "girlfriend" for one hour every Wednesday when he visits him grandmother. A week later, Kazuya encounters Mami again for the first time since they broke up. Kazuya then goes with Chizuru to meet his grandmother. After visiting her, they walk home together only to be spotted by his friends. When he tells them that they are dating, they are invited to a drinking session. At the session, Kazuya notices Mami is there too, and she proceeds to belittle him. Chizuru angrily calls out Mami, but Kazuya stands up for her. Once the session is over, Kazuya is walking home alone when Mami asks him if he wants to head to her place.

(Source: Wikipedia)