In Cauldron of Blood (1968), a blind artist's wife is murdered, and he becomes the prime suspect. Determined to prove his innocence, he embarks on a journey to find the true killer. As he delves deeper into the investigation, he uncovers a web of secrets and deceit, leading him to a shocking revelation.

Antonio and Rafael Lorca, two brothers with very different characters. Antonio returned to his farm after having made ​​a career as a singer in Latin America. Meanwhile, all these years has been to Rafael parental care and its fields and farms. When he returned to Spain Antonio realizes that Rafael is preparing his wedding with Carmen, the woman with whom he had always been in love.

Traumatized by the War of Algeria and by the accidental death of his wife and his son, Manu left the right road. His last caper was the attack of the Antwerp-Tangiers Express, carrying a precious cargo of industrial diamonds. But the whole affair was bungled and all of his accomplices got shot. The only survivor of this disaster, Manu now finds refuge in the mountain house of Lucia, the widow of a smuggler who lives alone there with her little boy.

A doctor invites his relatives to his castle, all the while planning to murder them when they arrive. However, when he himself is murdered, the relatives know they have to find the killer before he gets all of them.

John Lucero, who was born poor, became the richest of the region, his great love for horses was what led him to make this fortune. His fame transcended even beyond the borders of Spain.