The Secret Adversary

This is Agatha Christie's second ever mystery book (after "The Mysterious Affair at Styles") first published in 1922. The story begins on the Lusitania, when a young woman - Jane Finn - is given some secret papers before getting aboard a lifeboat. Four years later, young Thomas Beresford and Prudence Cowley meet up in London - both broke and unemployed. Retreating for tea and cakes, they decide up...