Judith Potts (Samantha Bond) is a retired archaeologist who is great at solving puzzles. Suzie Harris (Jo Martin) is a professional dog walker. And Becks Starling (Cara Horgan) is a mother and wife of the local vicar. Together they form The Marlow Murder Club.

Three murder cases unfold over the six episodes in the season. Each case covers two episodes to set up the murder and uncover the culprit.

These women are fun as well as intelligent and insightful. And, when combined with the professionals, they manage to solve murders in record time.

Not being sworn police officers, they have leeway when investigating the crimes. True, they are unconventional, but they are just what is needed when it comes to rooting out the killers.

The first story is a head scratcher. The popular mayor drops dead in the middle of a meeting. Everyone in attendance is a suspect, and during their investigation the trio uncover various aspects of each of them. How and why are the two questions always at the root of each murder. In this case, it was obvious – poison. But how did it get there and who put it there?

The second story is a bit more intricate as Becks is one of the suspects. During a university reunion of her friends, one of them is stabbed. With no one leaving the premises after the murder is discovered, the culprit has to be one of the group.

And the third story involves the death (another stabbing) of a famous chef during the launch party of his new book. The trio just happens to be at the party and jump right in the investigation which involves not only those in attendance, but the murderer is most likely one of the staff.

During the season there are some fun interpersonal stories that add to the enjoyment and entertainment of the show.

Judith has not one but two admirers. Only one, however, is worth pursuing. Suzie tries speed dating and encounters someone they all know who is secretly trying the same thing.

And Becks is at her wits end when her mother-in-law comes to stay for a while – too long as far as Becks is concerned. How can she keep her sanity with this woman who disapproves of everything she does, and says so. The trio manages to find a way to get her out of Becks’ hair, house, and town!

“The Marlow Murder Club” is based on the bestselling novels by Robert Thorogood, who wrote three novels. This season is an adaptation of the third book. Thorogood has said: “I can’t wait for audiences to join Judith, Becks and Suzie on their adventures as they solve a series of fiendishly puzzling murders.”

Season 3 premieres Sept. 6, 2026, on MASTERPIECE on PBS. Viewers can catch up on the previous two seasons with the PBS Member’s PBS Passport and on the free PBS app.