An illustrated novel with the first appearance of Tommy & Tuppence. The ship Lusitana has been torpedoed and a stranger has given a young girl a packet containing an important document. The stranger dies, and the girl, whose name is Jane Finn, disappears, and the packet is forgotten. Until, that is, a labour unrest starts in England and if the papers fall into the wrong hands it could prove deadly to the government. Tommy Beresford and Prudence Cowley (nicknamed Tuppence) know nothing of this when they unexpectantly meet. They go to a cafe and discuss what's been going on in their lives since they last met. Discovering that they're both currently unemployed, they come up with the idea of becoming adventurers," willing to do anything, go anywhere." After they depart, a man named Mr. Whittington approaches Tuppence, and he leads her to his office. He overheard their conversation, and he wants to propose a job offer to Tuppence. He wants her to go to France to a place called Madame Colombier's for about three months. When he asks her what her name is, she doesn't want her father to think anything bad, so she says," Jane Finn.", Mr. Whittington gets very angry and says, "How much do you know? And how much do you want?" Tuppence manages to get fifty pounds off him, then she leaves. She and Tommy discuss the situation and decide to try and find out who Jane Finn is.