When the pets from the Seaver family – Shadow the Golden Retriever, Sassy the Himalayan cat, and Chance the American Bulldog – accidentally get separated from their vacationing owners on a trip to Canada, they find themselves in the unfamiliar city of San Francisco. With home on the other side of the Golden Gate Bridge, the trio must navigate the mean streets of San Francisco, avoiding hazards both human and animal, to try and find their way back. Along the way, they encounter a group of street-smart stray animals known as Riley's Gang, who become unlikely allies in their quest for home.