Santo vs. Evil Brain

Santo was ambushed by three gangsters in a deserted alley and dragged to Doctor Campos's laboratory. There, Campos subjected him to injections and electric shocks to break his will and turn him into a docile servant under his control. Campos needed a powerful henchman for his criminal operations and chose the masked wrestler because of his strength and reputation.

The opening scene establishes that other scientists have recently been kidnapped, hinting at Campos's larger operation.

Campos used a combination of injections and electric shocks in his laboratory to break Santo's will. The process is described as a merciless regimen that transformed the independent hero into a weapon under Campos's control rather than a free agent. The same brainwashing technique was later used on other subjects, including the bank manager.

El Incógnito is a fellow undercover operative working alongside Santo. He uses a specialized device to locate Campos's hidden lair, providing crucial intelligence for the police. After finding the hideout, he defeats the brainwashed Santo, injects him with an antidote, and instructs him to pretend he is still brainwashed to maintain the ruse.

The mention of double identities and encrypted loyalties early in the film foreshadows Incógnito's reveal as another undercover agent.

After injecting Santo with the antidote, Incógnito ordered him to pretend nothing had changed because the brainwashing ruse was still valuable. By acting as if he remained under Campos's control, Santo could operate as a double agent, gathering intelligence and supporting the police raid from within the criminal operation.

The cell disintegrator is a classified formula that Campos promised to sell to an agent. It represented unprecedented power and could potentially destabilize the balance of power in the city. This explains why Campos kidnapped Doctor Lowel, he was also a scientist whose work likely related to the formula or its development.

Zambrano's warning about other scientists being kidnapped hints at Campos's interest in acquiring scientific knowledge.

Campos kidnapped Elisa, his own secretary, because she was a critical witness to his criminal schemes. Additionally, Zambrano deduced that Campos wanted to silence her testimony, as her knowledge of the bank robbery and his operations could threaten his broader plans. Her kidnapping also served as a way to draw out Gerardo, Campos's assistant.

El Incógnito used a specialized device to pinpoint Campos's hidden lair, tracing the location and tightening the investigation's noose. This intelligence was passed to Lieutenant Zambrano, who used the tip to plan and execute the raid on Campos's laboratory.

The earlier warning about other scientists being kidnapped adds context to the scope of Campos's operation.

El Incógnito returned to Campos's laboratory, fought and defeated the brainwashed Santo, and injected him with an antidote that reversed the brainwashing. This medical intervention restored Santo's free will, allowing him to rejoin the side of good while still appearing controlled to maintain the deception.

Campos held Elisa hostage at his house while Santo infiltrated through the roof and Incógnito created a distraction. When Campos shot Incógnito, Gerardo woke from his drugged sleep and joined the fight. Santo burst in and confronted Campos, just as Zambrano arrived and shot the villain. Campos died apologizing to Elisa, and the threat was neutralized.

Campos had brainwashed the bank manager, using him to orchestrate a calculated heist. When Elisa went to the bank to speak with the manager, she discovered the robbery in progress. Campos then kidnapped her to prevent her from testifying about the crime and his involvement, linking the bank robbery to his larger scheme of manipulating institutions.

The bodyguards of Doctor Lowel informed Lieutenant Zambrano that Santo, who they recognized as an undercover police agent, was one of the kidnappers. This revelation complicated the case significantly, as it meant Santo was acting under duress after being brainwashed, not willingly participating in the crimes.

Zambrano warned that other scientists had recently been kidnapped to establish the scope of Campos's conspiracy. This warning serves as crucial exposition, revealing that Campos was not working alone and that his ambitions extended beyond just controlling Santo, he was systematically acquiring scientific knowledge and talent for his criminal operation.