When a captain and his wife in Her Majesty’s Guard are murdered, Colin Pendragon and Ethan Pruitt are called to Buckingham Palace. Major Hampstead demands discretion to protect the Guard’s reputation, pushing Pendragon to solve the case swiftly under the threat of a media cover-up. Despite obstacles from Inspector Varcoe, Pendragon and Pruitt work against time to uncover closely guarded secrets and catch the killer, putting Pendragon’s integrity on the line.