Christian Stern, an ambitious young scholar and alchemist, arrives in Prague in the bitter winter of 1599, intent on making his fortune at the court of the Holy Roman Emperor, the eccentric Rudolf II. The night of his arrival, drunk and lost, Christian stumbles upon the body of a young woman in Golden Lane, an alley hard by Rudolf's great castle. Dressed in a velvet gown, wearing a large gold medallion around her neck, the woman is clearly well-born, or was, for her throat has been slashed. A lesser man would smell danger, but Christian is determined to follow his fortunes wherever they may lead. He quickly finds himself entangled in the machinations of several ruthless courtiers, and before long he comes to the attention of the Emperor himself. Rudolf, deciding that Christian is that rare thing, a person he can trust, sets him the task of solving the mystery of the woman's murder.