Nobita asks Doraemon for a Moshimo‑box and wishes that the world become a place where magic can be used. In this new reality, witchcraft replaces science and technology, and people rely on it daily, except for Nobita, who, as usual, struggles with spell‑casting. Frustrated, he decides to restore things to their former state, but his mother throws the Moshimo‑box away. Later, Doraemon and his friends encounter Professor Mangetsu, a scholar of magic and magical beings such as goblins, and his daughter Miyoko. They warn the group that the “Star of the Underworld” is dangerously approaching Earth’s orbit. With the planet’s future hanging in the balance, the friends must journey to the Underworld.