As the Thirty Years' War draws to a close, Johan Sokolewski, a lute-playing soldier, flees Warsaw with the Cossacks at his heels and arrives in Stockholm, where he becomes lutenist for the Swedish queen. On his first day at court, he learns that in the early hours of that morning, a body was discovered in the royal library. When the eccentric and aging queen mother discovers that her favorite book, a priceless sixth-century codex, has disappeared from its place in the library, she insists the thief and murderer are the same person. Evidence points to Zofia, the court astrologist, seen near the library that winter night, carrying what looked like a blade. Zofia is taken from her workshop and locked in a room under house arrest, but Johan believes she is innocent. When he defends her, the queen mother appoints him to lead the investigation. Failure to uncover the thief and murderer will lead to Zofia's conviction. Unable to refuse a royal command, Johan enlists the aid of his new friend Gunne, a dwarf who frequently entertains the queen mother. Gunne knows the courtiers and much more about Stockholm Castle, including secret passages in the palace. Together, Johan and Gunne follow a trail of false leads through winding corridors and bat-filled tunnels, where wax dolls and suspicious incidents threaten to end Johan's life.