Secrets hide in the Druid's Grove, in a murderer's heart, and in Niall Kier's past . . . October 1851. After millions of visitors and months of success, the Great Exhibition is winding down. Mr. Niall Kier and Miss Kara Levett are busy with the celebrations planned for the last weeks—and with all the commissions their involvement has brought them. Their artistic works stall, though, when the closing ceremonies are interrupted by a murder. Suddenly, a friend is under suspicion and the murder has been linked to the Druid's Grove, the secret society in which Niall is a member and Kara has just been inducted. They dive in, hoping to quickly clear their ally's name, except nothing is simple in the Grove and no one is exactly who they seem to be. Niall and Kara put their talents and resources to work once more, but they find that old, sinister secrets might be behind the present-day bloodshed. And as they investigate, it appears someone might also be digging about in Niall's mysterious past.