End of the Race — Laurie Halse Anderson

It all starts when an injured greyhound is brought to the clinic, and Maggie and Dr. Mac learn that a neighbor is keeping sick racing dogs at her house. They come from a dog track in Connecticut. Dr. Mac, Maggie, and Taryn, the newest Vet Volunteer, travel there to check on the condition of the dogs, and Maggie and Taryn decide to get to the bottom of the mystery on their own. It's risky, but it will be worth it if they can save these greyhounds!