1635, Aberdeen. A girl lies dead in a frozen garden. A young man goes missing after a drunken brawl. A sinister cloaked figure watches from the shadows.

The missing student, son of a Highland chief, is in Alexander Seaton's class. When the young man's companion turns up bruised and bloodied, suspicion mounts that he has murdered his friend. But Alexander is convinced that there's another explanation.

Drawn ever deeper into the mystery, Alexander realises that the man in the shadows is known to him and that the strange events in the town are linked to his own past.