Ringo no Ki wo Ueru

In the summer of her third year of high school, Mii's childhood friend Mayuka dies in a bus accident. She never knew why she got on a bus she didn't usually take... Now a university student, Mii moves into a new house and meets Maki, her neighbor. For some reason, Maki knows a secret about Mayuka...? When Mii and Maki meet, the truth surrounding Mayuka's death begins to unfold.

(Source: Shueisha, translated)