The Secret Adversary
by Agatha Christie
Tommy Beresford and Tuppens Cowley's old plague, full of lack of energy and funds, decides to form the "Young Adventurers" and declares themselves ready to "go anywhere and do anything." When asked by a British intelligence official to find a woman named Jane Finn who has disappeared with secret government documents, they discover that their bizarre ideas have led them into a web of complex intrigues, intelligence agents, suspicious personalities, missing government documents, fake clues, and very real danger.