Sometime after the events of the first film, Max and Duke's owner, Katie, meets and marries Chuck and have a son, named Liam, whom Max disapproves of at first due to his rough play but eventually softens up to him. Later, Max's overprotective feelings for Liam develop into an itch which prompts Katie to get him a dog cone from the veterinarian in an effort to lower his symptoms. Max's luck changes when Duke reveals that the family is going on a road trip outside of the city. Duke soon finds though that life on the farm is not what he thought it would be.