The story follows the title character (also known as God of Death No. 413) who serves the role of sending the spirits of the dead to the afterlife. The "heartwarming fantasy" also deals with parent-child love, friendship, and social issues such as childhood bullying.

Shinigami-kun's real name and other details have not been revealed, but he appears in his black suit and bow tie, saying "Congratulations, I'm here to take you to the next world!" Part of his important duties are to persuade someone who is about to commit suicide and prevent unexpected and accidental deaths, but as a novice, he breaks rules of the afterlife and makes decisions like a human.