In Victorian London, the botanist Irwin Molyneux and his wife Margaret Molyneux are bankrupted but still keeping the appearance due to the successful crime novels written by Irwin under the pseudonym of Felix Chapel. Their cook has just left the family, when Irwin's snoopy and hypocrite cousin Archibald Soper that is in campaign against the police stories of Felix Chapel invites himself to have dinner in Irwin's house. Margaret decides to keep the farce of their social position secretly cooking the dinner, while the clumsy Irwin justifies her absence telling the bishop Soper that she had just traveled to the country to meet some friends. However Soper suspects of Irwin and calls the Scotland Yard, assuming that his cousin had poisoned his wife. Irwin and Margaret decide to hide the truth to avoid an exposition of their financial situation, moving to a low-budget hotel in the Chinese neighborhood, getting into trouble.