The Secret Adversary

Hiring themselves out as "young adventurers willing to do anything" is a smart move for Tommy and Tuppence. All Tuppence has to do is take an all-expenses-paid trip to Paris and pose as someone named Jane Finn. But with the job comes a threat to her life, and the disappearance of her mysterious employer.

Now Tuppence's newest job is playing detective-because if there's a Jane Finn that really exists, she's got a secret that's putting both their lives in danger. The Secret Adversary, a detective novel by Agatha Christie, is her second published novel. The book introduces the characters of Tommy and Tuppence who feature in three other Christie novels.