After eating half a leaf of lettuce for lunch, Garfield tries to raid the refrigerator but is prevented by Odie, whom Jon has assigned to make sure the cat himself doesn't try to cheat on his diet.

Later, Garfield weighs himself on his talking weight scale and destroys it for comparing him to Orson Welles, and is repeatedly foiled by Odie when he tries to steal cookies, flour, salt and sugar.

However, Jon doesn't have a clue on how to prepare such a dinner; he forgot to thaw the turkey or leave enough time to thoroughly cook it and thus tries to compensate by raising the oven's temperature from 325 to 500 degrees Fahrenheit, ignores the stuffing, when told to "rub skin with butter" rubs it on his own skin, and throws all the vegetables in a pile in water on the stove (to which Garfield attempts to sabotage the vegetables by adding garlic powder).

As Jon leaves to check on the meal, Liz spends some time with Garfield, casually listing some of the symptoms of excess dieting, some of which he experiences (like irritability and fatigue) and others he obviously fakes (such as dementia and twitches).

As Jon distracts Liz by giving her a history lesson about Thanksgiving (and Liz dozes off), Grandma proceeds to cook the meal: she cuts the still-frozen turkey into slices with a chainsaw, adds white sauce then batters and deep fries the slices into croquettes, after which she prepares sweet potatoes by covering them with butter, brown sugar and marshmallows, finishing with "split-second cranberry sauce" (from the can) and pumpkin pie.

Afterwards, Liz declares that it was a wonderful meal and agrees to come back next year, then thanks Jon for inviting her with a kiss on the cheek.