- Jessamy Noyes - assistant to Dan Gilbert
- Dan Gilbert - a potter
- Coralie Gilbert, his wife
- Miss Leah Crocker - an old maid, "frightening, ramrod-backed, and acid-tongued"
- Miss Emmeline Crocker - her sister, a "fluttery, stupid little spinster"
- Titus Crocker, their brother, seen as simple
- John Bartlett, who rents a room to Jessamy Noyes
- Mattie Bartlett, his wife
- John Whitman, a wealthy Boston sportsman
- Harry Hurst, another wealthy Boston sportsman
- Tony Oliva, milkman
- Elisha Macomber - the only authority on the island
- Buck Edwards, chief of Medbury police
- Harvey Minden, Boston reporter
Locale: Penberthy Island, off the Massachusetts coast
At the isolated end of Penberthy Island lies the old Crocker place, run down, overgrown, penniless, and inhabited by the last of the Crocker line: three siblings ... Miss Leah Crocker (the boss), Miss Emmeline Crocker, and Titus Crocker (who is a little simple). To bring in some cash, they have rented a building to a potter Dan Gilbert and his wife Coralie. Dan has hired Jessamy Noyes as a summer assistant. The Crockers also made a deal with two flush Boston fishermen, John Whitman and Harry Hurst, to lease them exclusive fishing rights on their property.
Jessamy, who rents a room from John Bartlett in town, walks to the Crocker place to work and feels someone watches her on the isolated road; but no one is found. Titus Crocker goes bird hunting and finds a dead man on a hill. He comes back to report it, and when the scene is reached, the body is gone. The only evidence Titus can offer is a playing card, the three of diamonds, which he said he found with the body. Meanwhile, news reports from the mainland bring updates of a jewel theft ring which may be connected to the murder. Suspicion points at off-islander John Whitman.
Complicating the plot is a love affair between John Whitman and Coralie Gilbert,
The Elisha Macomber titles are always satisfying, and this one lives up to that standard. The island offers a closed environment for our suspect, and multiple red herrings. The periodic news reports from the mainland provide an intriguing parallel plot as the islanders keep their ears glued to their radios to follow progress. Of course, islanders always view off-islanders with suspicion anyway, so they will have to cope with that bias.
The three Crocker sibling provide a colorful element, with fully developed characters that seem so familiar to all of us.