It's Garfield's birthday and Jon forgets. He later remembers, and makes 8 lasagnas but is one short. Meanwhile, an unusual type of Alien which looks like lasagna and can speak English with an Italian accent arrives on Earth. They plan to invade the Earth, but are quickly scared away by Garfield's ravenous appetite.

A Bluebird gets trapped in Garfield's neighbor's garage leaving her eggs abandoned, forcing Garfield to look after them. The eggs hatch, and call Garfield mother. This episode marks the first appearance of Garfield's rival Harry, who is determined to eat the chicks.

Garfield disguises himself as "Catzilla" for Halloween, but people mistake him for the real Catzilla, a deadly creature who escaped from the zoo.

Garfield and Odie get their bodies swapped by a Saturnian alien when it finds out Odie is tormented by Garfield. Odie wanders off to all the people who hate Garfield without knowing they will hurt him so Garfield must protect his body from the neighborhood dogs, Herman Post and the Chef.

Odie digs up some bones and finds that they are from the very rare Brachiosaurus. Garfield tries to sell them to the local museum, but the museum curator instead wants to compulsory purchase and demolish Jon's house to search for more dinosaur bones.

Jon tests a cleaning robot.

Garfield and Odie watch a movie about a villain named Silent Jack and mistakenly believe Jon, with recent tooth surgery, to be Silent Jack. In the end Garfield, Odie and Squeak find out they were attacking Jon, but the real Silent Jack robs them.

Nermal finds a cat called "Agent X" who claims to be a Secret Agent, but really a runaway cat. Garfield becomes jealous as Agent X tells everyone about his adventures, so Garfield tries to prove he is a house cat named "Fluffykins".

Squeak and his family move in to Jon's house while Jon and Odie are out. Garfield allows Squeak's family to remain in the house on the condition that they be his servants. Jon comes back and Garfield has to remove Squeak and his family before Jon called Rat-Tator Pest, who's hefty bill would have meant that Jon would not be able to afford lasagna for years.

Garfield gets an awful tasting Pizza from Mama Meany's Pizza Palace, Vito's rival. Mama Meany is putting Vito out of business through coupons, contests and discounts and plans to expand the restaurant to take over Vito's. Garfield arranges for Eddie Gourmand to compare Mama Meany pizza with Vito's, bringing the closure of Mama Meany, and resumed success of Vito.

Nermal lives with Garfield for 10 days because his owner is out of town. Nermal fakes a leg injury and Jon feels pity for Nermal, making Garfield and Odie do whatever he requests. Garfield and Odie get rid of him so they could enjoy their normal house and lives once again.

Garfield searches for his teddy bear Pooky after he is stolen by a dog named Hercules.

Jon and Liz put Garfield on a diet and force him to exercise when an electronic talking scale tells him that he's overweight.

Jon has difficulty sleeping, so a Hypnotist attempts to put Jon under hypnosis to make him fall asleep at the sound of a horn. However, Jon hears Odie's bark before the horn, making Odie the hypnosis trigger.

Jon finds his old Accordion but Garfield doesn't like him playing it nor the very sound of it. Garfield tries to get rid of it, but in the end, the Accordion breaks and Jon gets bagpipes instead.

Jon wins a turkey in a competition, which he plans to cook for Liz. However, when it is delivered it is still alive. Garfield disguises himself as a turkey to get rid of the real one.

Odie gets taken to the dog pound as he's not wearing his license tag Collar. Garfield disguises himself as a dog to rescue Odie.

Odie falls in love with a shower brush. Garfield gets jealous as Odie is no longer paying attention to him and throws the brush in the recycling bin without Odie knowing it.

Jon and Garfield fight so much against what to watch on TV that they decide to go on a TV show called Pet Matchers.

Garfield gets rich after a Leprechaun gives him some good luck.

Odie becomes a monster-dog in the middle of the night and eats a lasagna that was for for Jon and Liz. Jon thinks that Garfield is responsible, and blames him.

Liz introduces Jon to her parents. Liz's father is a grumpy man, while Liz's mother has a canary named Petey - who Garfield tries to eat.

Garfield goes to visit Jon's little brother Doc Boy. But with no TV and no pizza, Garfield shows the farm animals how to live life his way.

Garfield is rejected from The Pet Show because he's too fat to enter, so Odie takes his place and competes against Nermal for lasagna.

Garfield and Odie get taken to another land through a magic mirror where Neferkitty (voiced by Susan Silo) and her Egyptian colony of cats live, planning their revenge on humans.