This well-crafted mini-thriller adapts a Dorothy L. Sayers story very nicely into the half-hour television show format, and it is also helped considerably by Everett Sloane's leading performance. It sets up the tension efficiently, adding some good touches as things play out. Hitchcock's opening and closing remarks, full of his morbidly dry sense of humor, also contribute to a very good episode.
The story stars Sloane as an easygoing businessman who starts to experience unexplainable attacks of indigestion, at about the same time that authorities are on the lookout for a deranged, murderous housekeeper. Sayers's story makes perceptive use of human psychology, and Sloane's performance is important in bringing this out. The last part features some good twists that work quite well. If you watch it a second time, you can then follow the ways that viewer perceptions are cleverly steered in one direction, while keeping open some other possibilities that are less obvious, but just as well-founded.
It's a good combination of story, adaptation, direction, and acting, making for an above average episode of this classic anthology series.