1889: Kitty Gray dreams of attending university and becoming a doctor, but when she is married off to Charles Maclean, one of Glasgow's richest and most eligible bachelors, her aspiration suddenly slips far from reach. Exiled to her new remote home in the Scottish Highlands, with its gargoyles, gothic arches and turrets, Kitty seeks solace in creating a restorative herb garden. Combining her medical knowledge and new-found fascination with herbalism, Kitty spends her days absorbed in a world of herbs and their healing properties until a devastating tragedy strikes... 2003: Caitlin Black arrives at Ardbray House determined to restore the crumbling mansion and Kitty's walled garden to their former glory, enlisting the help of long-time housekeeper Greer Mackenzie. But as Caitlin delves deeper into the history of this once magnificent home, she uncovers a past haunted by misfortune and grief. And beneath the blood-red roses that climb beside the bay window of the drawing room, a human skull is about to be unearthed. The truth that has held Ardbray House captive for so long is surfacing, and with it, the heart-breaking secret of the herbalist who once lived there.