Yuno Gasai is a first‑year high school student who enjoys an ordinary routine. She shares a good relationship with her parents and maintains a modest group of friends. Yet she feels an uncanny absence, as though a vital person is missing from her world—someone so essential that it feels like she has lived an alternate life, yearning to stay close to them.
After a school field trip to the seaside, Yuno returns home; during the night she begins receiving mysterious messages from a voice that only she can hear. The voice reveals the identity of the person she longs to meet and urges her to find them. Soon, Yuno is transported into a strange realm, with the sole purpose of reuniting with this forgotten figure. Despite numerous challenges, she will do everything necessary to meet her beloved once more.