Life on a Leash (2002)

Stella's got a new job, a new car, and the perfect apartment. But something's missing - other people. Enter Kong, a giant brown-and-black stray dog who shows up when Stella is changing a flat tire. Suddenly her life is being pulled into the world of dogs and the oddball crowd that lives with four-legged friends. She enjoys the companionship and the community but keeps pulling back as Kong literally drags her out of her shell.