Barbie and Billy Winslow go to play a baseball game and reluctantly bring Marmaduke along to be the mascot. Barbie has to sit out the last inning and Marmaduke steps in to take her place with their team down one to nothing. Can Marmaduke help the team win the game?

An alligator escapes from the zoo and is really hungry when he spots Heathcliff going through some garbage cans. Can Heathcliff avoid the alligator and keep from being on the menu?

Marmaduke and the kids are playing in the park and Mr. Nicely is watching them play when J. D. Taggart drives up and says that he is repossessing the lot if the loan is not paid quickly. Can they raise enough money in time to pay off the loan and save their playground?

Marmaduke sees a female bulldog named Missy and he instantly falls in love with her but there is a male bulldog that lives in the same yard with her and he doesn't like Marmaduke. Will Marmaduke win her over or will the other bulldog keep Marmaduke away?

Heathcliff goes to the carnival and runs into Crazy Shirley. Can Heathcliff dodge the crazy-about-him girl?

The Winslow family goes to watch a rocket launch and the rocket is being piloted by a robot named Bruce when Marmaduke chases a cat into the rocket and it blasts off. Can Bruce the robot keep Marmaduke from messing up the mission and can Marmaduke return to earth to his family?

Maramduke finds a cat genie at the beach.

A catnapper catnaps Sonja and holds her for ransom and Heathcliff has to rescue her.

Marmaduke fantasizes about being a superhero and stopping a robot that is plundering the city.

The Winslows rehearse a play causing Marmaduke to think he’s no longer wanted.

Heathcliff is shanghaied by Grubs (as a captain) and forced to catch mice, but Heathcliff and the mice scam Grubs, he gets fed up and he makes Heathcliff walk the plank.

Marmaduke sneaks aboard ship with the Winslows and now he has to guard an ape to earn his keep. Can Marmaduke keep the crafty ape from causing trouble?

The Winslows take a trip to the beach and Marmaduke tangles with a shark. Can Marmaduke catch the shark or will it be vice versa?

Heathcliff read in the paper that a reward is offered for the capture of an escaped six foot mouse. Can Heathcliff capture the raging rodent?

Marmaduke dresses up to go out trick or treating. Will he get treats or is he in for tricks?

Barbie takes a dare that she and Billy can stay in a haunted house for an hour and they bring Marmaduke with them. Can they stay there for an hour with the ghost of Captain Clum trying to scare them away?

Heathcliff receives a letter and briefcase from a cute female spy and is told that he must deliver it to the dock. Can Heathcliff make it to the dock with the letter before a couple of enemy spies grab it?

Mr. Winslow wants to take Marmaduke to a veteran's BBQ, but Marmaduke hears him wrong and thinks that he means to take him to the veterinarian and Marmaduke goes into hiding. Can Mr. Winslow find him and get him to the park to enjoy the BBQ?

The Winslow family go on a camping trip and Marmaduke sneaks in to go along. How will Marmaduke do on his first camping trip?

Heathcliff talks about how interesting the day of rugged pirates and chiverlous captains awhile in his bath time, and thinks of his great ancestor Captain Horatio Heathcliff, where the ancestor of Heathcliff takes Princess Sonja to her father's land but is attacked by Blueberry the Pirate.

Marmaduke digs up a chunk of gold an Phil and Dottie head into town to get it check and leave Marmaduke with the kids to guard the claim. Will the tough old prospector, who has seen all this, take the claim from them?

Marmaduke is sleeping on the couch when he hears a TV commercial offering to train dogs for the police department in the Canine Corp. Can Marmaduke prove himself worthy enough to be in the Canine Corp?

Heathcliff and Iggy are competing against Muggsy and Spike in the annual Pet 'N Pal Cross-Country Sled Race and the winner gets a gold trophy and all the pizza they can eat at Luigi's Pizza Parlor. Will Heathcliff and Iggy be able to overcome all of the obstacles that Spike and Mugsy put in their way and win the race?

Mr. Snyder is planning several ways to keep Marmaduke out of his yard and keep him from digging up and burying bones. Can Marmaduke get his bones back before he loses them for good?

Marmaduke is left at the house while the Winslows go to the store and he starts to dream about the wild west. Does Marmaduke get to enjoy the dream or is it going to be a nightmare?

An small alien attempts to abduct Heathcliff to his shuttle.

Marmaduke interrupts the filming of several movies.

Marmaduke babysits for Aunt Kay's dog Sweetums while she and Barbie go to the charity bazaar. Sweetums has a collar worth $50,000 and there is a crook that has been waiting for an opportunity to grab it.

Heathcliff and Granny are looking at old pictures and reminiscing and we see flashbacks to when Heathcliff had just moved into the neighborhood and he first met Spike and the other dogs. How does little kitten Heathcliff get along with Spike and his buddies?

The mailman sees Marmaduke coming and decides to hide in the mailbox until he passes by. Marmaduke then passes a construction site where he discovers 4 kittens in danger. He decides to watch them until he can find them a permanent home.

When told that if a leprechauns is caught you can get its pot of gold or any wish. Marmaduke tries catch it with the leprechaun using tricks to outwit Marmaduke.

Spike and Heathcliff end up in a castle with a scientist named Dr. X, who tries to switch their body, with the help of his Frankenstein.

Billy wants to take Marmaduke to the school for show-and-tell and puts roller skates on him to get there. Can Marmaduke make it to the school or will he have an accident on the way?

The Winslow's are on a trip to the supermarket and Marmaduke is trying to help drive. When they finally get parked Mr. Winslow accidentally leaves his keys in the car as Jake and Grugsy Glugg come out of a bank that they have just robbed. Little do they know that Marmaduke is in the back seat and plans to foil their robbery.

Spike chases Heathcliff but is unable to catch him. He decides to build a robot cat to try and help out.

The kids let Marmaduke outside to greet their father Mr. Winslow as he gets home from work. Once inside there is a knock at the door. It's the police and a member of the lost pet society who claims that Marmaduke is actually the lost dog of Mrs. Van Upton named Hobart. They two men haul off Marmaduke upsetting the entire Winslow family. The kids follow Marmaduke in an effort to get him back.

Barbie and Billy have a lemonade sale, when the neighborhood bully, Meany Molligan steals their money they got for selling lemonade, it's up to Marmaduke to return their money from Meany.

Gophers are devouring the Winslow garden and Marmaduke is sent to scare them off. It turns out to be a bigger job than he imagines. Marmaduke tunnels through the entire neighborhood trying to catch them causing problems for everyone.