Captain Diego Alatriste has just returned from the war in Flanders and is ready to hire himself out as a bodyguard and general sword-for-hire. Diego tries to help a father and two brothers rescue their sister from a convent where she is being held captive. This is not a place of worship like a regular convent but, rather a place of debauchery that might have some connection to the court of King Phillip IV. The father's attempt to get  his daughter back is met with a threat to reveal the family as `conversos' (Catholics who have Jewish blood, which the inquisition frowns upon.  The punishment for that infringement is to burn at the stake.)  

During the attempted rescue things go terribly wrong. Alatriste's ward, Inigo Balboa, who is only 13 years old, falls into the hands of a long-time enemy and becomes a victim of the Inquisition. Inigo is determined to keep from implicating Alatriste in anything that will cause him trouble, and the inquisitor is determined to get Alatriste in his clutches.  They stop short of serious torture because of Inigo's very young age, but he is slated to be burned at the stake.  Diego's great friend, the Spanish poet, Francisco de Quevedo, is called upon to help with the rescue attempt, and he has some interesting ideas of his own.

Rich in historical detail, this entertaining novel by Spanish author Arturo Perez-Reverte just may be addicting.  I absolutely fell in love with Diego, and his exciting escapades.  I will have to read the rest of the series; this is number two, with seven volumes promised.