Portugal is at war with Castile. Melgaço remains loyal to the Castilians. Inês, a woman with a violent past arrives to join the siege of the traitorous city. King João I, the "Master of Avis," asks Inês to help him deal with a "demon" that causes terror in Portuguese hearts.

What Inês discovers is that her past has returned to put her to the test. This will trigger a spiral of betrayal and bloodshed. A conflict that will culminate in an epic battle between the symbols of Portugal and Castile.