Yuno Gasai lives a normal life as a first-year in high school. She gets along well with her parents and even has a small circle of friends. However, she cannot help but feel as if someone is missing from her life, someone so important to her that it was as if she had lived another life trying desperately to stay with them.
After a class trip to the beach, Yuno returns home; but in the middle of the night, she receives strange messages from a voice only she can hear. The voice informs her of the person she is desperate to meet and that she must find him. Soon, she finds herself in a mysterious realm, her only goal being reunited with the person she cannot remember. Though obstacles stand in her way, Yuno will stop at nothing to meet her beloved once again.