Miss Marigold Manners may be steeped in the etiquette of her old-money Boston family, but she is also an accomplished, modern woman and an avid student of archaeology who can handle any situation with poise. When the death of her parents leaves her too destitute to pursue her academic career and she receives a letter from a distant relative on Great Misery Island, Marigold decides she must do what any person of superior sense and greater-than-average curiosity would: she mounts her trusty bicycle and heads up the craggy, fog-shrouded coast of New England for a date with fate.

Marigold arrives at Hatchet Farm, a moldering, gothic pile of a house inhabited by relatives so mired in the sins of the past, they have no future. She sets out to modernize the recluses with a brisk, ruthless efficiency, but her well-intentioned plans to manage their lives lead to malice—and murder. Marigold spies a body floating in the stormy waters surrounding the island, and her suspicions immediately turn to her hostile, weapon-wielding relatives when one of the local girls turns up missing. And she might not be the only one.

When another dead body is found in the garden of the estate, Marigold finds herself accused. She must enlist the help of an eccentric, colorful cast of friends and found family to save herself—and everything she holds dear.