The events described take place in the late 30s of the last century. For solving a complex and intricate crime in his hometown of Ashford, Inspector Michael Riley was rewarded with a tour of the castles of Scotland. He goes there as part of a small tourist group, which stays at the cozy country guesthouse Travelers Refuge. However, soon a murder occurs here, and Riley begins to investigate it. There is no evidence in the case, the motive for the crime is not clear, but the inspector is sure that the crime was committed by one of the guests of the boarding house. A short time later, the hidden criminal commits another murder, but Riley figures him out and brings him to light.