After an encounter with a black cat, Garfield gets cursed with bad luck.
In the Arbuckle house, Garfield sleeps on a sofa, but wakes up when he thinks it is Monday. He checks the calendar, and is relieved to find that it is not Monday. Feeling ecstatic, he makes two sandwiches and gulps up one, just as he was about to rest on a lawn chair, Garfield says hello to a depressed black cat, who says his disdain over life. Garfield shrugs it off and tosses his sandwich in the sky to catch it in his mouth, but walks toward a rake, whacking his face, and the sandwich lands on Garfield's face.
Garfield comes inside complaining about the rake and walks toward the living room, turning on the TV to watch his favorite show, "The Wrong and the Tasteless". but a TV announcer says that a nine-hour documentary will take place instead. Garfield complains and bangs on the TV screen, which explodes after he sees a label which says not to pound on it, Garfield is blown out of the house and lands in a birdbath. Harry comes to say hello, but Garfield explains that today was perfect, until all these incidents happened. Harry asks if he saw a black cat, to which Garfield affirms, saying he looked sad. Harry says that it's Jonah, and says that he is a jinx. Harry beats a hasty retreat from Garfield after a meteor and flower pot fall on Garfield's head. Garfield then tries to think of a way to counter his bad luck. Garfield goes to the cellar and finds a horseshoe. but after he kisses it and tosses it, the horseshoe hits a hornet hive, which a horde of angry hornets chase after the unfortunate cat. Garfield jumps inside a garbage can for safety. but when a garbage truck comes, a garbage man picks up the can Garfield is in, and pours him in the truck and to the recycling plant.
Soon after, as Garfield decides to locate Jonah, he is hit by a flower pot, a mallet, and Eddie Gourmand on a couch. When he sees an elephant fall on a man's car, he thinks Jonah crossed a lot of people's paths, and decides to follow the trail of bad luck. Thinking that his curse is lifted, a farmer's fruit cart crashes into Garfield. Afterward, just as Garfield thinks that he'll never find Jonah, he sees Jonah in front of him. Garfield asks Jonah to lift his curse, but says that he cannot, explaining that he's been depressed, since the day his girlfriend, Mindy, dumped him. Garfield then gets a plan to get Jonah and Mindy together again.
At dusk, Garfield and Jonah sit on a bench to wait for Mindy to come out for her evening stroll. Garfield and Jonah approach her, but Mindy notes that Jonah's lack of happiness made her break up with him. Garfield appeals to Jonah after he places a slice of grapefruit in the depressed cat's mouth, making it look like Jonah is smiling. This gets Mindy's attention. Garfield then tells the seemingly-smiling cat to tell her he loves her. Jonah confesses his feelings to Mindy, making her say that all is forgiven. Garfield congratulates Jonah with a pat on the back, which makes him swallow the grapefruit slice, losing the smile. Mindy thinks that Jonah cannot help being gloomy. Defeated, Garfield walks away, but slips on a banana peel, making Jonah laugh at Garfield's expense. Mindy in her surprise, sees Jonah laugh for the first time. Jonah then says that it is the first time he has ever laughed, making Mindy think the both of them could be together again.
One day later, Garfield explained his adventure to Harry. Just as Harry congratulates Garfield for resolving the Jonah problem, a piano falls on Garfield's head. Garfield says that the Jonah curse was lifted, then proceeds to sob and state that the day was Monday.
- When Eddie Gourmand falls down, Garfield breaks the fourth wall by saying "That was a recurring character!"