Shaggy and Scooby are very tired, and after a good night's sleep (before which they consumed so much food) they decide to take up a training course to get fit. However this did not go as planned, and Shaggy and Scooby secretly discuss that Robi is a terrible trainer, and lots of negative things about him – but Robi hears them quite by accident, and sends his dog, Sparky, to continue his job while he runs away from his house. Phibes learns of this. Now Shaggy and Scooby must rescue Robi as Phibes has a nasty surprise for him.