Garfield, the lazy and sardonic orange cat, lives a comfortable life with his owner, Jon Arbuckle. His favorite activities include sleeping, eating lasagna, and pestering Jon's other pet, Odie the dog. One day, Jon unexpectedly brings home a mysterious ancient artifact he found at a garage sale, not realizing it holds special powers. When Garfield accidentally triggers its magic, he finds himself with unusual abilities that turn his mundane life upside down. Meanwhile, Jon's new neighbor, a retired archaeologist named Dr. Donna Meyers, senses something strange is afoot and becomes curious about the artifact.

As Garfield grapples with his newfound powers, he must also fend off a group of determined thieves who have discovered her whereabouts and seek to steal the artifact for their own nefarious purposes. Enlisting the help of Odie and Dr. Meyers, Garfield embarks on a series of comical and adventurous escapades to protect his home, all while learning valuable lessons about responsibility and friendship. The trio faces numerous challenges and hilarious mishaps as they strive to outwit the thieves. The story builds up to an exciting confrontation that will determine the fate of the artifact and Garfield's peaceful existence.