The Summer Guests is an excellent, tightly written mystery that blends small-town intrigue with sharp intelligence work, proving once again why Tess Gerritsen excels beyond medical thrillers. Set in a picturesque seaside town in Maine, the novel introduces readers to a world where quiet streets and ocean views conceal secrets that refuse to stay buried.

The story centres on Maggie Bird, a former spy who has retired to this peaceful coastal town, hoping for a quieter life. She is far from alone in her past, however. Her close-knit circle of friends, all former CIA operatives, share her history, sharp instincts, and a lingering inability to ignore unanswered questions. Together, they form an informal group known as the Martini Club, whose casual name belies their formidable investigative skills.

When a teenage girl goes missing while on holiday with her wealthy family, the tranquillity of the town is shattered. The girl’s disappearance quickly becomes the community’s primary concern, and suspicion falls heavily on Maggie’s neighbour. Convinced of his innocence, Maggie becomes determined to clear his name, even as pressure mounts for a swift arrest. The missing girl’s influential family wants results, not doubts, and the town’s acting sheriff finds himself caught between public expectation and Maggie’s persistent reasoning.

Despite being officially asked to stay out of the investigation, Maggie and the Martini Club press on regardless. Their experience consistently puts them a step ahead of the acting sheriff, whose frustration grows as the amateur sleuths uncover leads faster than official channels. Maggie must rely on her finely honed persuasion skills to keep the focus off her neighbour and ensure the investigation follows facts rather than convenience.

The mystery deepens when a skeleton is discovered in a nearby pond. Initially thought to be connected to the missing teenager, it is later revealed to be the remains of a woman who vanished many years earlier. This revelation adds a chilling historical layer to the story and reinforces the idea that this seemingly idyllic town has long harboured dark secrets. Jo, one of Maggie’s closest allies, recognises that the Martini Club’s unique background makes them exceptionally qualified to dig into long-forgotten truths.

What makes The Summer Guests especially enjoyable is its balance of suspense and character-driven storytelling. The plot is well-paced, the mystery is easy to follow without being predictable, and the camaraderie among the Martini Club adds warmth and wit to the narrative. Gerritsen handles the transition between past and present seamlessly, creating a story that feels both cosy and quietly unsettling.

The Summer Guests is a well-written, engaging mystery that introduces a compelling new group of amateur investigators. With its strong setting, intelligent plotting, and memorable characters, it leaves readers eager for the next instalment featuring the Martini Club. Highly recommended for fans of smart, character-led crime fiction with a strong sense of place.