Those Summer Days Vol. 4 (Kodansha, 2018)

Six former classmates met up at their school reunion, only to be thrown back in time 10 years. After they receive mysterious texts exposing the wrongdoings of their past, they begin to doubt one another. Takumi vows to change the past and save Taruoka from his fate, but Yuka is focused on making sure she sees her child again, and Taichi wants to rekindle his relationship with her. And right when their efforts seem futile, they learn what really caused Taruoka's horrible accident.