Fred Jones' pen pal, Alejo Otero, invites him and Mystery Inc. to visit him and his family in Veracruz, Mexico, which is being terrorized by a monster that its citizens believe to be "El Chupacabra".

There, they meet a suspiciously hyperactive museum guide who leads them into a performance about ancient Mexican customs, during which Daphne is forcibly volunteered and kidnapped.

As the Otero family give offerings to Alejo and Luis' father and hope for Charlene's safe return, they are seemingly visited by his ghost, who urges them to sell the hotel in English.

Alejo is unconvinced while Fred discovers a good luck charm that Charlene gave Luis earlier is actually a tracking device and presses a button on it.

Scooby and the Oteros' dog, Chiquita, track the subsequent beeping sound to a shed containing a man in a skeleton costume controlling the ghostly illusion.

However, the group ensnare it in wiring and expose it as the tour guide, who reveals she was an actor at one of Smiley's theme parks, where they fell in love and concocted the Chupacabra scheme.