The Secret Adversary , Agatha Christie’s second novel, introduces Tommy and Tuppence, the two much-loved mystery-solving adventurers.

The novel centers around a mysterious young girl, suffering from amnesia, who was present on the sinking of the Lusitania . As Tommy and Tuppence try to unravel the mystery, they find themselves embroiled with mysterious millionaires and the dangerous politics of nation-states.

Contemporary reviews of The Secret Adversary were positive, and the success of the novel paved the way not just for future Tommy and Tuppence adventures, but for a long, storied career of literary success for Christie.