Tenshi no Keisei: 16-nengo ni Mezameta Watashi

A girl named Umi wakes up after a 16-year-long sleep following an accident she experienced during her second year of high school. She discovers that her parents are older than she remembers and that she now has a younger sister who is the same age Umi was when she fell asleep. Confused and disoriented, she enters a home filled with unfamiliarity and no memory of her past. It becomes clear that her parents are concealing details about the accident. As Umi attempts to piece together her fragmented memories, glimpses of her past slowly resurface, intertwining with the present in a suspenseful narrative involving the two sisters.