The Mystery of the Pantomime Cat is an installment in the Five Find-Outers and Dog series. The plot centers around a crime, possibly a theft, that occurs during a local pantomime performance, with a character dressed as a Cat potentially being involved or a key witness. The Find-Outers must navigate the world of the theater, costumes, and false identities to solve the puzzle, often requiring them to go backstage to find the truth.