When a professor (Jeff Goldblum) develops a vaccine that eliminates human allergies to dogs, he unwittingly upsets the fragile balance of power between cats and dogs and touches off an epic battle for pet supremacy. The fur flies in director Lawrence Guterman's family-friendly comedy as the feline faction, led by Mr. Tinkles (voiced by Sean Hayes), squares off against wide-eyed puppy Lou (Tobey Maguire) and his canine cohorts.