A healthy young labourer is found dead in a shallow ornamental pond on the vast country estate of Lady Philippa Armstrong and her son Jonathan. While the tragic incident initially appears to be nothing more than a straightforward workplace accident, Rose and Raj are called in to investigate glaring discrepancies. After all, how does a strong young man manage to drown in mere inches of water?

Meanwhile, Joe overhears staff from Gallowbrae Hall discussing the suspicious death. Having spent much of his youth stealing from the estate, Joe knows the local personalities and the layout of the property inside out. Believing he can be of genuine help to an unconvinced Rose, he eagerly inserts himself straight into the investigation. Finding themselves reluctantly paired up once again, Rose and Joe must untangle the messy, tight-knit relationships of Gallowbrae's eccentric inhabitants.

At the centre of the drama are the Armstrongs, an old-money family desperately holding onto what's theirs while caught in a fierce controversy over a new rewilding scheme. This scheme will close off public land to reintroduce sensitive wildlife and plants, sparking intense outrage from one local inhabitant in particular. Adding to the tension are Maxine, the devastated housekeeper who keeps her cards close to her chest; Whittick, the grouchy gamekeeper fiercely determined to protect Gallowbrae at any cost; and Gavin, the angry intruder and conspiracy theorist who views the aristocratic family and everything they stand for as completely abhorrent.

Struggling to navigate the complex social dynamics of the estate, Rose reluctantly accepts Joe's persistent interference. Together, the duo soon uncover a dark web of deep-seated secrets and lies within the family and their devoted staff.