The story's main characters are a pair of casual paranormal researchers who are experimenting with the idea of astral projection. One night, one of them inadvertently succeeds in projecting his spirit from his body, which is then taken possession of by a malevolent entity in his absence. His partner receives a vivid sensation of him calling out for help and rushes to his residence, only to find him absent and the place in shambles. The researcher continues to search for his partner and learns that he has perpetrated a series of violent incidents around London. He seeks the aid of a medium, who channels his partner's spirit and finds that he has fallen down a well and subsequently been abandoned by the possessing entity. They locate the well and rescue him, after which he recounts the story of his possession.