The Gladstone Bag — Charlotte MacLeod

Sarah Kelling's Aunt Emma is a woman who throws herself into good works, such as leaping from a burning building into a net to raise money for a fireman's widow.

Now old friend Adelaide Sabine needs a hostess for her isolated summer place on Pocapuk Island, and Emma leaps again. She'll enjoy a quiet summer of rest, relaxation, and repairing the stage jewelry belonging to her pet Gilbert and Sullivan troupe while she keeps a benevolent eye on the artists and writers who'll be occupying Adelaide's six guest cottages. She packs up the baubles in her old Gladstone bag and heads for the coast of Maine.

On the ferry, Emma is drugged and her bag temporarily stolen... could someone have mistaken the paste jewels for real diamonds?

On the island, she's barely settled in when her Gladstone bag is heisted again, a trespassing scuba diver is found dead, and a mysterious stranger is off on a rampage of attempted murders. Emma won't stand for such a shocking breach of island etiquette. She enlists niece Sarah and nephew-in-law Max Bittersohn for a spot of long-distance detecting... and sets about digging a trap for a ruthless villain.