Thirteen at Dinner (1985)

Actress Jane Wilkinson wants a divorce, but her husband, Lord Edgware, refuses. She convinces Hercule Poirot to use his famed tact and logic to make her case. Lord Edgware turns up murdered, a well-placed knife wound at the base of his neck. It will take the precise Poirot to sort out the lies from the alibis - and find the criminal before another victim dies.