William is an insufferable prodigy who accidentally summons a demon and somehow that makes him worse, not better. The real comedy isn't the supernatural chaos, it's watching a kid so convinced of his own logic that he tries to rationalize demons out of existence. Every episode is William's absolute confidence colliding with the one thing his intellect cannot calculate.

William Twining is a brilliant seventeen-year-old aristocrat, proud of his lineage and devoted to modern science, who faces his family's financial ruin. When his uncle's business collapses, William returns home and searches the family estate with the butler for anything that can be turned into cash. His search leads him to a hidden underground room left by an ancestor, where a magical seal waits. William accidentally summons Dantalion, a demon who reveals that William is the Elector, the only one with the power to choose a temporary ruler of Hell while Lucifer lies in a deep slumber. William is also told that he descends from King Solomon, but the stubborn realist refuses to believe any of it, denying that magic or the supernatural exists at all. Meanwhile he stands at the center of an ongoing conflict between Heaven and Hell. The result is a comedy with fantasy, mystery and supernatural elements.