Tomas Nevinson, a retired MI6 agent, is working for the British Embassy in Madrid when his former handler, the sinister Bertram Tupra, offers to bring him back inside for one last assignment. His mission: to catch and, if necessary, kill a terrorist gone to ground in Northern Spain after bombings in Barcelona and Zaragoza. The trouble is there are three suspects - all women - and it may not actually be any of them. To find out, Nevinson must move incognito to the small town where the three women separately live, and become an intimate friend to each, in the hope of uncovering a clue . . .

A philosophical thriller with a climate of suspense to rival le Carre and a psychological depth that is purely Marias's own, this is a novel that explores the deepest of human questions: in what circumstances can killing be called just?