In contemporary Japan, Yuu Tachibana lives a seemingly ordinary life with his beloved family. However, Yuu harbors a secret: he has lived a past life in another world, making his current life his second. Having no one to call family in his previous life, Yuu cherishes his family all the more.

One fateful night, Yuu discovers an unidentified phone in his room. The message displayed on its screen is cryptic and foreboding: [Do you want to save your family from their terrible fate?]

With a sense of dread, Yuu is faced with a choice: [Yes] or [No].

Yuu must decide if he is willing to risk everything to protect his loved ones. Will he choose to save them, or let fate run its course?