"The Mystery of 31 New Inn" by R. Austin Freeman is a detective novel written during the early 20th century. The story centers around Dr. Jervis, a medical doctor who is drawn into a perplexing case surrounding a mysterious patient named Mr. Graves, who appears to be gravely ill under peculiar circumstances that suggest possible poisoning. At the start of the narrative, Dr. Jervis reflects on his connection with the influential detective John Thorndyke while recounting a recent incident in his practice. He receives a call from a messenger, summoning him to attend to Mr. Graves, a patient who has refused medical help until now. As he arrives at a dimly lit house, he is met by a rather anxious housekeeper. Once confronted with Mr. Graves, he recognizes alarming signs that suggest opium poisoning, leading him into a web of secrecy and uncertainty. The strange atmosphere, the behavior of the housekeeper, and the ominous presence of Mr. Weiss establish a tense dynamic, raising questions about the actual nature of the illness, the motivations of those involved, and the dark secrets they might be concealing. (This is an automatically generated summary.)