Ariadne Oliver (Zoe Wanamaker, Harry Potter) returns to join forces with Poirot to investigate a drowning at a Hallowe'en Party. As they look further, they uncover a series of mysterious deaths in the village that could be connected. Adapted by Mark Gatiss (Sherlock).
Visit the Website: http://www.pbs.org/wgbh/masterpiece/mystery/
Episode #4116 / Length: 1 hour, 26 minutes