Circus animals are being mistreated, and Charlie and Itchy are on the case. They learn that an elephant named Nelly is abused, and it's their job to videotape it and send it to Animal Control.
Charlie and Itchy are sent to a military base and show a kid how to have fun, but Anabelle also sent them there so Charlie would learn some respect for authority figures.
Charlie and Itchy are assigned on a mission to watch an absent-minded scientist. Armed with a Miracle Dog Tag, supposed to be used for emergencies only, Charlie persuades Itchy to let him have it, turning himself into a human.
Itchy and Charlie write a report for David on the history of all dogs and how they helped society.
Charlie and Itchy take a stroll on the upper-class neighborhood and meet a rich show dog named Thor, who looks exactly like Charlie. Charlie wants to know what it is like to be pampered, and Thor wants to know what it is like to be a free-spirited street dog, so the two switch places. When Thor's agility contest comes up, and Charlie's expected to do a dangerous move, Charlie soon realizes that switching places between each other is more difficult than at first thought.
Charlie dreams a bad future for himself. When it takes him to a future where dogs live under the oppressive rule of the canine-hating 'Deliverer', he decides to change his ways before it's too late.
Carface gets his hands on a dangerous substance able to turn dogs into monsters. He and Killer taint Charlie's dog food, and Charlie turns into a monster. Carface and Killer plan to use Charlie to steal for them, and then turn Charlie in. Itchy learns about this situation and goes to rescue his best friend.
Charlie is assigned to train three potential angels, but when he fails, and he needs their help, they mess up, getting Charlie in deeper trouble.
Itchy tells the story of the amazing Double Dog Dare and how he saved the world.
Itchy accompanies Bess to her dog school reunion, with Itchy pretending to be of pedigree. Afghan Hound Tiffany humiliates Bess, sparking Charlie to prank her, but it only makes everything worse. After Tiffany puts fleas on Itchy, the beam she's standing on collapses. With the other dogs unwilling to help, it's Itchy to the rescue.
Charlie recounts how he met Itchy, and how he'd been a bad dog to a pair of puppies arguing over a bag of dog food.
Charlie becomes obsessed with being recorded doing a heroic act. That is, until Itchy almost drowns, but the reporters catch him saving Itchy, and the two get to go to an exclusive hotel suite.
Itchy gets so scared that he can't help Charlie, who decides it's time for Itchy to face his fears. He tells Itchy that they are spending the night in a supposedly haunted mansion, unaware that it's not just superstition.
Charlie is put on Heavenly Trial by Belladonna, who alleges that he's been abusing his angelic position. If found guilty, Charlie will be stripped of his duties and sent to work on the other side.
Charlie, Itchy and Sasha itch and scratch their way through everything and anything in an effort to save Christmas from the wicked hellhound Belladonna, who wants to use dogs from all over the world to ruin Christmas.