33 Half Moon Street - SA - A Widow in Black

Concerns arise over the security of a valuable consignment of animals from South Africa, including a rare grey reebuck, which a zoology professor, Mervyn Levers, is overseeing. After arranging for security during transportation to the London Zoo, Mervyn suddenly collapses and dies of a heart attack en route, leaving guard Gail Hamilton and driver Cannon to manage the situation. However, it soon becomes evident that Mervyn was murdered using a black widow spider, which was released from a capsule placed in his hat. Subsequent investigations reveal that a Professor Tobin, who was spotted near the scene, is actually a Russian agent planning to steal the rare buck as a gift for the Kremlin. The animals, except the grey reebuck, are eventually reported as released into the wild after Tobin's arrest, exposing a clever confidence trick and conspiracy behind Mervyn's untimely death.