After the Spooks' difficult mission in Cuba, Morton Chapel has accepted Kathryn Lennox's help in attempting to treat his daughter, Megan. The girl has been catatonic since she witnessed her father shoot her demented mother Madeleine. But Chapel speaks of possession rather than insanity; an hypothesis the rational Kathryn finds it difficult to accept. And Madeleine's father, a mining industry mogul, intends to exact his revenge from the Spooks leader.