Who is the “secret adversary”? For her second novel, Agatha Christie created the youthful, jazz-era characters Thomas Beresford and Prudence “Tuppence” Cowley. Down on their luck, Tommy and Tuppence decide to become adventurers for hire and swiftly find themselves in an international plot to bring down the British government. Time is not on their side as they work to uncover the mysterious “Mister Brown.”