In Veracruz, Mexico, Fred Jones's pen pal, Alejo Otero, invites Mystery Inc. to visit him and his family as they face a terror the locals believe is the legendary El Chupacabra. The Otero clan runs a struggling hotel, and their guests are scarce, a hardship that intensifies the already tense atmosphere around Alejo, his wife Sofia Otero, their son Jorge Otero, their mother Doña Dolores, and Luis, Alejo’s brother, along with Luis’s American fiancée, Charlene Otero. Over a tense dinner, the family is joined by Diego Fuente, a business partner of Alejo and Luis’s late father who wants to buy the hotel, but the Oteros refuse his offer and send him away. Alejo later explains to Mystery Inc. that the purported monster has been scaring away potential patrons, hinting at a larger threat to their livelihood.
Determined to help, Fred Jones leads the investigation, enlisting the Otero brothers as they search for the creature. A foreboding message in Spanish on the gang’s van, the Mystery Machine, warns them to stop digging, but the team presses on. The group splits up: Velma Dinkley and Daphne Blake join the Oteros with Fred, while Shaggy Rogers and Scooby-Doo stay with the van, unaware that someone has drained the brakes. In the woods, the explorers encounter El Curandero, a medicine man who urges them to study history and warns of grave danger, all while the Oteros come under attack from the very creature the town fears. Despite the peril and the brake failure, the team reunites, and they make a hasty retreat to a gas station after a tense chase.
Back in town, they visit a local history museum, convinced this is the clue the Curandero mentioned. There they meet a remarkably hyperactive museum guide who leads them into a performance about ancient Mexican customs, during which Daphne Blake is forcibly volunteered and then kidnapped. A hidden passage leads the group to an Aztec pyramid setting, where they find Daphne and manage to rescue her, only to be pursued by tourists who are manipulated by an animatronic eagle, seemingly outraged at any desecration of sacred sites. After escaping, the team returns to Veracruz to reevaluate clues, noting a grammatical error in a threat that a fluent Spanish speaker would never make.
The next day, on the Day of the Dead, the Mystery Inc. crew travels to the local cemetery. Dolores explains that Charlene has been abducted by El Chupacabra, and the family offers offerings to Alejo and Luis’s father, hoping for Charlene’s safe return. A ghostly visitation seems to confirm the father’s presence, and he urges the family to sell the hotel—an advice that Alejo resists. Fred discovers a seemingly innocent good luck charm Charlene gave Luis is actually a tracking device, and he activates it. The device leads Scooby-Doo and the Oteros’ dog, Chiquita, to a shed where a man in a skeleton costume controls the ghostly illusion. They capture him, exposing him as Mr. Smiley, a theme-park owner who hatched the Chupacabra scheme to scare Veracruz into selling out to his new development.
Before Mystery Inc. can wrap up the case, El Chupacabra strikes again, but the team traps it by wiring, revealing that the “creature” is actually the tour guide—who confesses she was an actor at one of Smiley’s theme parks, where she and Smiley fell in love and plotted the ruse. Luis asks what happened to Charlene, but the guide insists she’s gone and tells him to forget about her. When Luis pleads for help from his father’s spirit, the offerings begin to disappear—except for Charlene’s, which remains. Velma then reveals that the guide is actually Charlene, who planned to dupe the Oteros out of their money after marrying Luis. Fuente steps in, admitting he knew of Smiley and Charlene’s plot and was trying to warn the Oteros and Mystery Inc. In the end, Smiley and Charlene are arrested, and Mystery Inc. celebrates the Day of the Dead alongside the Otero family, grateful for the truth that saved a family’s livelihood and kept Veracruz’s traditions intact.
- Charlene Otero can be seen as a crafty foil who mixes romance with deceit, and her arc intertwines with the family’s struggle to protect their legacy.
- The story blends mystery with cultural festivity, using the Day of the Dead as a backdrop for revelations, teamwork, and a hopeful resolution.
The film honors the enduring teamwork and wit of Mystery Inc. even as it traverses a vibrant Mexican town, unveiling that greed and showmanship can disguise themselves as fear, and that truth, loyalty, and a little bit of humor are often the strongest clues in solving a mystery.
