Too big to run

"Zach's mom has a new patient--a giant dog named Maxi who has been helping her owner train for a marathon. Maxi's knees can't handle all that running and now she needs an operation. Time for the kids in the Pet Rescue Club to help! Together they find a way to raise money for Maxi's surgery and come up with a great way for Maxi to find the perfect new career!"--Back cover.