Scooby runs into his old kennel mate, Axel, who has become part of the police K-9 unit. Axel begins acting like he is better than Scooby, prompting Shaggy and him to try to solve the mystery themselves to prove Axel wrong. Meanwhile, Daphne pretends to be Fred for a day, whilst the gang solves the mystery of a trash monster terrorizing the local garbage dump.
