Kono Yo no Hate de Koi wo Utau Shoujo YU-NO

In YU-NO, Takuya Arima is a high school student whose father, a respected historian, has disappeared under mysterious circumstances. During summer vacation, Takuya receives a strange package from him along with a letter describing the existence of parallel worlds. What seems like an impossible theory becomes real when the device inside the package lets him move between alternate dimensions, each one exposing different versions of the same people, events, and choices. As Takuya follows the trail left behind, his search for his father turns into a larger mystery about the secrets hidden across those worlds and the reason his father vanished. YU-NO builds its story around shifting possibilities, the uncertainty of what is real, and the emotional weight carried by every path he follows. Across the franchise, the investigation links family, memory, and fate, with Takuya forced to compare timelines, gather clues that only make sense across multiple realities, and decide which truths can survive when every branch of the world can change the answer.