At the Fish Mart, Mr. Schultz is having a conversation with someone in the phone for them to deliver fish, but they are not able to. Mr. Schultz runs out of fish quickly due a certain cat that can eat faster than they could deliver, Mr. Schultz hangs up the phone and decides to close the shop and go fishing to replenish the fish in his store.
The Winslows rehearse a play causing Marmaduke to think he’s no longer wanted.
Heathcliff is shanghled 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?
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 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?
Marmaduke interrupts the filming of several movies.
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.
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.