Mark Ablett has been entertaining a house party

Tony Gillingham, a stranger who has just arrived to see his friend Bill, decides to look into Mark Ablett's disappearance. Gillingham plays Sherlock Holmes to his younger counterpart's Doctor Watson, and the two go through the novel almost in a lighthearted manner as the clues pile up and hypotheses arise.

The Red House Mystery was an instant hit; Alexander Woollcott considered it "one of the three great mystery stories of all time," however Raymond Chandler slammed Woollcott for it in his article The Simple Art of Murder (1944), calling him "quite a fast man with a superlative." Chandler wrote on the novel by A. A. Milne.