「You were originally meant to be reincarnated in another world, but as that world is currently oversaturated, we have decided to 'rewind' you back to the real world where Kosei Shinzaki lived.」

Kosei Shinzaki (30) was struck by a light truck just as he exited the venue after his junior colleague's wedding after-party.

Only his body underwent a 'reverse playback' in the present world.

Although his body reverted to that of a 15-year-old, he inexplicably remains in the same era as before his death.

With the addition of family members who shouldn't have existed then, his family interactions are now different from 15 years ago.

Despite being a loner with social anxiety during his school days, he now gets to experience a high school life vastly different from 15 years ago.

A socially awkward, introverted loner in his late twenties.

This is the story of his life (and youth) do-over.