Two years after the matriarch of the Argyle household is found beaten to death, the case is considered closed. Her adopted son Jacko was convicted of the crime, protested his innocence to the end, and died in prison after serving only a few months of his sentence. Then Dr Arthur Calgary, a geophysicist newly returned from an Antarctic expedition, arrives at the family home with an account that should bring relief: he gave Jacko a lift on the night of the murder, providing the alibi that was dismissed at trial. Instead of gratitude, his news lands as a fresh shock. If Jacko could not have done it, then the killer was never caught, and the murder was committed by someone inside the family. Calgary feels honour-bound to see justice done, but his disclosure forces the surviving Argyles to look at one another with renewed suspicion. The dead woman's husband, his secretary, the four other adopted children, and the long-serving household staff each carried private resentments toward a controlling mother who chose them. As old grievances surface and quiet alliances strain, the question is no longer who was punished but who has been protected by a convenient lie. The narrative weighs how the proof of one person's innocence becomes an ordeal for everyone left under a cloud of doubt.