Seth is a boy who seeks to become a great magician, and a group of witches who seek to travel to the Radiant. Radiant is a mythical land that spawns monsters called "Néméses" which fall to the world from the sky. While traveling, they are also hunted by The Inquisition.

Ho Won is a young woman who struggles to find a steady job. Tired and hopeless, she attempted suicide. Hospital check-up discovers she might have terminal illness. Soon after, a furniture company accepts her as a contract worker. Faced with a possibility of dying, Ho Won decides to just let herself loose. Her newfound bold attitude puts her at odds with her workaholic manager Woo Jin.

A nationwide manhunt for Hank Venture leads to untold dangers and unexpected revelations, while The Monarch is literally out for Dr Venture's blood. An imposing evil from the past reemerges to wreak havoc on the Ventures, The Guild, and even the Monarch marriage—it will take friends and foes alike to restore the Ventures' world to order… or end it once and for all.