When Judith Potts, a seventy-seven-year-old crossword setter, witnesses a brutal murder while swimming in the Thames, the local police dismiss her claims. Determined to uncover the truth, she embarks on an investigation, joined by a dog-walker named Suzie and the Vicar's wife, Becks. Together, they form the Marlow Murder Club, quickly realizing that they are entangled in a dangerous game with a real-life serial killer.
