Renowned Hollywood actors Robert and Stella Drury live on the outskirts of London. Their glamorous life is disrupted when Robert returns from Italy with the alarming news that their son, Mike, has been kidnapped. Curiously, no ransom is demanded. Instead, the kidnapper arrives at their home, requesting to stay as their guest for the next forty-eight hours. As the Drury's grapple with this unusual situation, they encounter a series of mysterious events and visitors whose true intentions are shrouded in secrecy. Francis Durbridge, celebrated for his detective serials for BBC radio and television, masterfully intertwines elements of mystery and suspense, prompting audiences to ponder not just "whodunit," but "whydunit."