"KIM Ja-hong… KIM Ja-hong… KIM Ja-hong!" After hearing someone call his name 3 times, Ja-hong (CHA) feels his spirit lifted up in the sky and is transported to an invisible world where all human beings will eventually end up. Ja-hong, a humane and devoted firefighter, is killed on the job while trying to save a child's life. With the guidance of three afterlife guardians – Gang-lim (HA) the leader, Hewonmak (JU) the security, and Deok-choon (KIM H) the assistant - Ja-hong is taken to the afterlife. He must pass a series of 7 hells over the course of just 49 days to gain a chance for reincarnation. The guardians assist Ja-hong for one reason: if they help reincarnate 49 souls in 1,000 years, the king of afterlife, Yeomra (LEE J), will reincarnate them as well. Ja-hong is their 48th potential reincarnation. Ja-hong goes on a journey to pass all 7 hells, in which he is tried on 7 sins - murder, indolence, dishonesty, injustice, betrayal, violence, and filial impiety. At every stage, Ja-hong's life is shown to be selfless, and he smoothly passes through most of them. Ja-hong soon learns that if he successfully passes all 7 hells, he will be given a chance to appear in anyone's dream before being reincarnated. He earnestly wishes that he can say one last good bye to his aging mother, and is determined to pass all the trials to make this happen. During his journey, however, Su-hong (KIM D), is accidentally killed while serving in the military. Angered and aggrieved, Su-hong becomes a vengeful spirit, a restless and evil spirit that wanders the living world. The appearance of the vengeful spirit also shakes up the afterlife, which consequently obstructs Ja-hong's journey. Gang-lim heads to the living world and chases after Su-hong to investigate his untimely death. But as circumstances of Su-hong's death and Ja-hong's life are uncovered, it becomes more difficult to prove Ja-hong's innocence and his fate is all the more uncertain.