“N or M?” is a compelling espionage thriller by Agatha Christie featuring her lesser-known sleuths, Tommy and Tuppence Beresford, embroiled in a World War II-era mystery. Set against the backdrop of wartime Britain, the novel revolves around Tommy and Tuppence being recruited by British Intelligence to infiltrate a seaside guesthouse and uncover a network of fifth columnists—spies working against their own country. The couple adopts aliases to blend in and, amidst a diverse array of guests, investigates suspicious activities, seeking to unmask the elusive traitors. Agatha Christie skillfully crafts a tale filled with suspense, intrigue, and unexpected plot twists, showcasing Tommy and Tuppence’s resourcefulness and teamwork as they race against time to uncover the spies and prevent potential threats to national security. Through its evocative wartime setting and the Beresfords’ daring escapades, “N or M?” captivates readers with its blend of espionage, mystery, and the resilience of the human spirit during a tumultuous period in history.