When Mackenzie Miller's aunt needs a foster home for one of the dogs at her shelter, Mackenzie jumps at the chance. Buster is so sweet and cuddly, and Mackenzie is sure he'll cheer up her stressed-out mom. And helping Buster find a forever home? Mackenzie loves a project!

Buster is an older dog who acts like a puppy -- which, it turns out, means he's a lot of work. Mackenzie wants to be the best foster mom ever, but she also has school; and her best friend, Sheera, needs help reconciling with her cousin, Yasmin; and her mom has just gone from overworked to unemployed. And Buster just keeps -- well, busting up Mackenzie's plans! Can she make it work, like she always does? Or has Mackenzie bitten off more than she can chew?