The episode starts with the Monkees stuck in El Monotono, Mexico because the Monkeemobile has broken down. They enter a cantina where they meet a waitress named Angelita, and almost immediately, she and Davy fall in love. Davy comments that her name means "little angel." She, in turn, asks what the name David means, but, interrupted by a joke from Mike, he doesn't answer. Soon, the Monkees run afoul of El Diablo, a bandit who basically runs the town. He abducts Davy because of his romantic involvement with Angelita, whom he claims is his girl, and after the rest of the Monkees pose as bandits to infiltrate El Diablo's gang and rescue Davy, El Diablo challenges Micky to a duel at high noon.
The meaning of the names Angelita and El Diablo match how these characters treat the Monkees and also highlight the contrast between them. Angelita (whose name means "little angel") falls in love with Davy, but El Diablo (whose moniker means "the devil") abducts and threatens to torture him and tries to kill Micky in the duel.
The name David means "beloved," which fits well with the situation in this and many other episodes where a girl instantly falls in love with Davy.
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On the DVD, one of the trivia items is:
When Michael (El Nesmito) wonders whether they [the Monkees in disguise as bandits] should carry a club card or some badges, Micky (El Dolenzio) sneers, "Badges? We don't need no steenking badges!" which is a nod to the character Gold Hat from The Treasure of the Sierra Madre (Warner Bros., 1948).
There are further similarities in that Gold Hat is also a bandit and The Treasure of the Sierra Madre also takes place in Mexico.