Preston Michaels is found dead. Specifically, his arm is found in the guts of a dead shark, as he apparently fell off of his boat. When Mark is named executor of the dead stockbroker's will, he soon discovers that Preston was murdered. Suspicion falls under a few people, and near the top is Preston's wife, Beatrice... and his other wife, Colorado rancher Terri... and his other other wife, Florida nutritionist Heather.
"Left-Handed Murder" displays symptoms of the following tropes:
- His Name Is...: Raymond Bergman calls up Mark, telling him he has figured out who the killer is... and wouldn't you know it, the killer whacks him on the swede.
- Secret Other Family: Preston reveals in his video will reading to have three wives in different states who are unaware of each other's existence.
- Stealing from the Till: Evan's motive is that he was embezzling from Preston's company for years.
- Video Wills: Raymond, Preston's lawyer, shows to Mark that his client has left a video to be played at the will reading, in which he introduces the gathered legatees to each other; an important task, since most of them haven't met before and come into the room believing they're his widow.
