Santo vs. the Kidnappers aka Santo contra los secuestradores begins with Interpol’s Office of Special Investigations sending Santo to Ecuador to investigate the kidnaping of Pedro Miller, a former counterfeiter. It is believed that Miller is being forced into working for a counterfeiting gang. Santo knows Elsa, Pedro’s sister, who works as an exotic dancer in a Quito nightclub owned by don César. Elsa’s “chauffeur” is cabbie Evaristo, who drives a antique jalopy. Santo’s assistants in Ecuador include the blonde Rosita. They are attacked by a gang of thugs and they fight. Rosita draws the attention of the police by firing several shots into the air, and the criminals flee.
Evaristo wins 3 million sucres on a horserace. A long sequence follows, as Evaristo, Santo, Elsa, Rosita, a policeman friend of Evaristo, and a judge (Carlos Suárez) celebrate his good luck by visiting the cabaret where Elsa works, a street fair, and the resort city of Guayaquil. While in Guayaquil, Santo is shot with a poisoned dart. Back in Quito, Evaristo discovers that his betting slip was a counterfeit!
The chief of the gang tells his henchman Carlos to kidnap Elsa and Santo. Pedro must create counterfeiting plates for them or Elsa will be killed. Santo asks Evaristo to wait in his hotel room in case an important phone call comes through. While there, Evaristo helps himself to Santo’s whiskey, and leafs through the wrestler’s scrapbook. Eventually, he tries on one of Santo’s spare masks, and knocks himself out while “shadow wrestling.” Evaristo dreams that he is the victorious Santo who is congratulated by a trio of young women after a match. While he sleeps, the kidnappers enter the room and abduct him, believing he is Santo. However, the real Santo hides in the trunk of their car and is taken to their hideout. Although Santo defeats the henchmen, they cannot identify their boss.
Meanwhile, the masked villain has kidnapped Elsa, thus forcing Pedro to complete the fake plates. Santo arrives in time to save their lives, defeating the gang leader and exposing him as don César. As the film ends, Santo prepares to depart for Mexico. He gives his car to Evaristo, and makes a date to meet Rosita in Acapulco. Elsa and her brother thank the masked hero. As the film ends, Evaristo wrecks his new car into an ambulance, which is carrying his policeman friend, now restrained in a straitjacket due to Evaristo’s outrageous behaviour!