A long-lost friend returns from the past to propose a lucrative investment to Airin's father, something very special: the purchase of a castle in Scotland. Airin, Sherlock, and Arsen accompany Mr. Adler on his journey north. However, the beauty of the mansion on the banks of the Clyde River is not enough to hide its threatening atmosphere. Disturbing nighttime messages and the arrival of an eccentric traveler from afar make the mystery even denser. And Airin is about to discover that the truth hidden within the walls of the castle may change her life forever.