Summoned to Edinburgh after another inexplicable vision, Dr. Peter Ainsley and his sister, Margaret Marshall, are shocked to discover their good friend, and Margaret's secret lover, has been arrested for murder. Dr. Jonas Davies, a celebrated surgeon and newly appointed professor at the University of Edinburgh Medical School, was found at the grisly scene with the bloodied surgical knife at his side, but both Ainsley and Margaret know that is hardly enough evidence to convict a man. With a police inspector determined to prove Dr. Davies's guilt and his medical colleagues distancing themselves from the nightmare, it falls on Margaret and Ainsley to prove beyond a shadow of a doubt that their friend had no motive to kill his fellow professor and didn't perpetrate the crime. As the investigation moves forward, however, it becomes clear it won't be enough to convince the court Dr. Davies didn't kill the professor. They have to find the person who did, along with enough evidence to convict him before the Scottish judicial system sentences Jonas to hang.