When one of the villagers asks Kat to clear out her dead sister's bedroom, she's thrilled to find a miniature replica of her mother's Carriage House among some junk. When she shares her discovery Lady Edith is eager to show her the matching replica of Honeychurch Hall that has been languishing in the vast attic for decades. Unfortunately, when they look there, it seems to have been stolen. Suspicion falls on a woman who's holidaying in the newly installed shepherd's hut in the walled garden. Although there is something off about the tourist, Kat believes the culprit is fellow antique dealer, the odious widower Sir Monty Stubbs-Thomas who has been showing an interest in the missing dolls house. As the body count begins to rise, Kat realises that the missing miniature harbours a vital secret that one particular person is willing to kill for.