Blood on the Borders — Judith Cook

This historical thriller, whose protagonist is inspired by a real 16th-century doctor named Simon Furman, is full of period detail that is reflective of the political intrigues of the times. On May Day 1592, after a night of revelry and a day tending the sick, Forman falls into bed utterly exhausted. Soon afterward, he is woken by a man on his doorstep who is dying from a sword thrust, and the next morning Forman is summoned to Whitehall, accused of harboring enemies of the state. To prove his innocence, he agrees to journey to Edinburgh on a secret spying mission. But once he enters the borders between Scotland and England -- where the bloodthirsty Reivers vow a life for a life -- he realizes that death is stalking him. As one gruesome murder closely follows another, Dr. Forman must act quickly to identify a ruthless killer before his own life is put in jeopardy.