At a difficult place in his marriage and career, a middle-aged man gets a shot at a do-over when he's transformed back into his 18-year-old body.

Having died unexpectedly, firefighter Ja-hong is taken to the afterlife by 3 afterlife guardians. Only when he passes 7 trials over 49 days and proves he was innocent in human life, he’s able to reincarnate, and his 3 afterlife guardians are by his side to defend him in trial.

Hyo-joo (Ha-neul Kim) is a temporary teacher at a boys' high school and Hae-yeong (In-yeong Yu) is a fellow teacher who is the school board chairman's daughter. One day, Hyo-joo witnesses Hae-young locked in a passionate embrace with a boy and she starts feeling an inexplicable sense of humiliation towards Hae-yeong.