Toshiue no Anata

Takaya hasn't seen his older cousin Saki in years, but when his parents leave on a trip, he is placed under her care. That same night, Saki has a few too many drinks, and the two of them end up sleeping together for the first time. The encounter changes the dynamic between them, and Takaya finds himself drawn to her in a way he never expected.

However, things quickly become complicated. Takaya has a new girlfriend, but from his perspective, the relationship is not going well. Whenever they go out together, Saki constantly gets hit on by other men, leaving Takaya frustrated and jealous. He begins to question her feelings toward him, unsure if their night together meant anything to her or if she is simply moving on. As he struggles with his own emotions and the awkwardness of their new situation, Takaya must decide whether to pursue a deeper connection with his cousin or let her go.