Santo contra Capulina plot
Capulina is a night watchman in a warehouse for an import and export firm, but sleeps most of his shift. Two bandits break in to steal a certain box, but are surprised by Santo. A fierce fight breaks out. Finally, Capulina wakes up from his sleep and he locks Santo so that the two gangsters can escape. Later he tells that he had locked up the wrong person by mistake. Santo and the commissioner open the box that the two had tried to steal. They find broken pottery in it, in which diamonds are hidden. They realize that there must be more valuable things in that warehouse and decide to keep an eye on them. Meanwhile, however, the cunning Capulina has managed to get hold of a mask like Santo wears.