A blind doctor from Girona, Isaac, travels to Perpignan for the wedding of his friend David's son, and also to help treat Arnau Mars, a knight and David's patient, who was seriously wounded in an attack. But while Arnau is trying to find out who his enemy is, an innocent apprentice dies. Perhaps he was mistaken for David or even Isaac? Now Isaac's supernatural ability to distinguish between evil and good, and Arnau's desperate desire to survive become their only weapon capable of preventing an even greater tragedy...