The Arsenic Labyrinth (Lake District Mysteries, 3)

Meanwhile, historian Daniel Kind is immersing himself in the work of John Ruskin, whose neighbors created the Arsenic Labyrinth. A shocking discovery makes it clear to Hannah that there is not one mystery to solve, but two, and she turns to Daniel for help in untangling the secrets of the past. As Hannah and Daniel struggle to resist a growing but dangerous attraction, Guy's plan to make a quick buck runs into trouble, and he has to resort to desperate measures. Someone is determined to kill to keep their secrets safe.
Set against the stunning backdrop of the Lake District in winter, the novel depicts how passionate relationships can lead to obsession and murder.