The Mystery Inc. gang have gone their separate ways and have been apart for two years, until they each receive an invitation to Spooky Island. Not knowing that the others have also been invited, they show up and discover an amusement park that affects young visitors in very strange ways.

When a professor develops a vaccine that eliminates human allergies to dogs, he unwittingly upsets the fragile balance of power between cats and dogs and touches off an epic battle for pet supremacy. The fur flies as the feline faction, led by Mr. Tinkles, squares off against wide-eyed puppy Lou and his canine cohorts.

When Phil and Debbie Winslow relocate from their native Kansas to the sunny climes of Orange County, their big-hearted, havoc-wreaking Great Dane gets a taste of the dog's life, California-style.

A drug sniffing agent canine is a target for an assassin boss so the FBI calls Witness Protection to send him somewhere else. Meanwhile a single Mom puts her 6 year old boy James in the care of her irresponsible, mailman, neighbor, Gordon, when the babysitter bails on her. Meanwhile, an assassin mob boss hires 2 goons to kill Agent 11....