Some convicts escape, led by an assassin who is also a marquis, and they terrorize the towns they pass by demanding money and murdering.

The king sends an emissary to Curro Jiménez with the mission that, in exchange for pardoning him, he catches an adverse political group that hides in the area.

A brother-in-law of El Gitano is mysteriously murdered and a crescent moon is engraved on his temple. Other victims also appear with the same mark. Curro finds a young woman who is also following in the footsteps of the man from the Media Luna.

A young man, son of a doctor, trained in liberal ideas, decides to imitate Curro Jimenez to implement justice, for this reason he kidnaps the owner of a mine that cruelly exploits the miners. At the doctor's request, Curro Jimenez must intervene to teach a lesson to his imitator and to a young miner who accompanies him in his adventure.