Three pets (Chance, a young dog unfamiliar with the world; Shadow, an aging, wise dog; and Sassy, a snobby cat) are left behind when their owners go on vacation. Unsure of what happened ...

Shadow, Sassy, and Chance are back ... They meet scruffy bully dogs and a gang of rebel dogs who are all abandoned and have started their own group. Also looking for them is a "Blood Red Van ...