This thrilling story starts with a pharmacist receiving a threatening anonymous letter warning him of his impending demise. What follows is a gripping tale of murder, mystery, and deception. As the plot unfolds, nothing is as straightforward as it appears, leading to a challenging and intricate journey towards the truth. The movie stays true to the excellent book and maintains a high level of suspense throughout. With superb direction, an incredible cast, and Gabriele Ferzetti delivering his best performance, this film will keep you on the edge of your seat from start to finish.