"The Secret Adversary" is a mystery novel by Agatha Christie, first published in 1922. It introduces the characters of Tommy and Tuppence, a pair of clever, adventurous young people who form a partnership, calling themselves "Young Adventurers Ltd." The story is set in post-World War I Britain, where economic hardship and political unrest are prevalent.The plot revolves around a missing woman named Jane Finn, who was entrusted with sensitive government documents but disappeared five years earlier. Tommy and Tuppence, in need of money and excitement, embark on a quest to find Jane Finn and the documents, which are of vital importance to the British government.Their investigation leads them into a world of espionage and political intrigue, involving various shadowy figures and a mysterious mastermind known only as "Mr. Brown." Throughout the novel, Christie weaves a complex web of red herrings, unexpected twists, and turns, culminating in a surprising revelation of the true identity of the secret adversary.The book is notable for its witty dialogue, fast-paced action, and the charming partnership of Tommy and Tuppence, which set it apart from Christie's other works that typically feature a solitary detective figure. "The Secret Adversary" marked the beginning of a series of novels and short stories featuring these characters, showcasing Christie's versatility as a writer beyond her famous Hercule Poirot and Miss Marple series.