Case History: While out for a walk, Scooby sees a prize poodle kidnapped and races to find the rest of the gang, who listen to the radio broadcast an update on a rash of dognappings. They visit one of the victims, Buck Masters, who thinks that the dognappings are related to an upcoming dog show. The gang decide to play the hunch, substituting Scooby as a decoy for Champion, a prizewinning Great Dane belonging to another show competitor. The ploy works, and Scooby is grabbed by the dognappers. Shaggy gives chase on a motor scooter but loses the dognappers' truck when he is menaced by a ghostly Indian on horseback. Meanwhile, the dognapper's ringleader, a figure in an Indian witchdoctor's costume, recognizes that Scooby is not Miller's Great Dane and has his henchman put Scooby on a rail car and send him down the mountain.

The rest of the gang, following the tracking beacon on Scooby's collar, catches up with Shaggy, and they then all watch as Scooby goes racing down the railroad track. Shaggy leaps onto the railcar, brakes it, and rushes it back to safety just ahead of the midnight express. Scooby leads them back to where he had been taken, an abandoned Indian village high up in a cliff. No sooner do they arrive than the witchdoctor appears and warns them off. But the gang separates and press on. Fred and Daphne once again meet the witchdoctor, and Daphne vanishes when Fred goes to investigate the stone idol in front of which the witchdoctor had been standing. Meanwhile, Scooby also becomes separated from Shaggy and Velma; following a passage, he finds Daphne (who's been tied up) and the imprisoned dogs. The two of them round up the rest of the gang, free the dogs, and use them to chase and tree the witchdoctor, who they unmask as Buck Masters. It had been Masters's plan to kidnap all the dogs who might have beaten his own dog in the competition and then release his dog in time to win.

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