Three years ago, young Lord Cassia set off on a mission entrusted to him by the king...and walked straight into an ambush. Taken prisoner, his friends executed, left to rot in a prison cell while a deadly plague swept the land — Cas is no longer the boy who set out for glory.

Newly released from his imprisonment, Cas wants only to return to his home in the mountains and forget the horrors of the past, to forget the newly-ended war and the bodies that piled high when cemeteries could no longer hold all those who sickness took. But home is not what he remembers: his castle has become a refuge for the royal court. And they have brought their enemies with them.
 
When an assassin targets those closest to the queen, Cas is drawn into a search for a killer... one that leads him to form an unexpected bond with a brilliant young historian named Lena. Cas and Lena soon realize that who is behind the attacks is far less important than why. They must look to the past, following the trail of a terrible secret—one that could threaten the kingdom’s fragile peace and plunge it back into war.