Haltingly, a boy tells his fearful story to Scotland Yard officials - how he alone had witnessed from the vantage point of his commuter train a scene of terror in a dingy room . . . a blood-chilling tableau framed in a lighted window, glimpsed for a moment between patches of fog, and then gone. Chief-Inspector Johnson listens tolerantly, yet official credence can hardly be given to such a tale. Terry Byrnes is an impressionable, imaginative lad. No crime of violence has been reported in the Battersea area, and if the boy has witnessed murder, where is the corpse? But if Scotland Yard is not worried, Janet Lapthorn is; and sometimes a fretful woman can be a powerful agent in the processes of justice. She has a number of questions which demand answers. Why have her letters to her close friend, Felicity Hilton, gone unanswered? Why has Felicity abandoned her husband, Alastair? Why has Alastair lied about his wife's whereabouts? To come straight to the point, where is Felicity Hilton? The evidence is disjointed. The clues are scattered. But slowly the mists of conjecture dissolve - as the police, like patient archaeologists themselves, reconstruct the hideous form and face of an unspeakable crime.