Virtuoso violinist Gideon Davies has lost his memory of music and his ability to play the instrument he mastered at the age of five. One fateful night at Wigmore Hall, he lifted his violin to play in a Beethoven trio... and everything in his mind related to music was gone. Gideon suffers from a form of amnesia, the cure for which is an examination of what he can remember. And what he can remember is little enough until his mind is triggered by the weeping of a woman and a single name: Sonia. One rainy evening, a woman called Eugenie travels to London for a mysterious appointment. But before she is able to reach her destination, a car swoops out of nowhere and kills her in the street. In pursuing her killer, Thomas Lynley, Barbara Havers and Winston Nkata come to know a group of people inextricably connected by a long-ago crime and punishment no one has spoken of for twenty years.