1593: Sir Robert Carey is tasked by the King of Scotland with finding and killing the young engineer calling himself Jonathan Hepburn. There have been two dangerous attempts on King James's life and Hepburn is at the back of both of them. Plus the troublesome Catholic Earls have been doing deals with the King of Spain again, planning to bring Spanish troops to the West Coast of Scotland and march them into England.

Killing Hepburn will be difficult. He's clever and ruthless, enjoys murder. His family are the skilful and respectable Hochstetters, German miners who have mined the Cumbrian Hills on the Queen's behalf for decades. Of course, they insist that Hepburn is innocent.

Worse, Carey finds that his nerve isn't what it was since the events in Dumfries in the summer of 1592. He struggles to overcome his strange terror of the dark mines where Hepburn has taken refuge.

Meanwhile Carey has no idea that Lady Widdrington is in deadly danger.