Dark Horse (Starlight Animal Rescue #4) - Dandi Daley Mackall

Starlight tosses her head, and I know instantly by the tightening I feel in her back that something's wrong. . . . Nothing unusual I can make out. . . . Then I smell it. Smoke.
Meet 18-year-old Hank. He's Catman's cousin and the all-American, popular, good guy at Starlight Animal Rescue. But a tragic fire has Hank questioning everything―including his ability to rescue anything, even himself. With a burned, wild horse and a lost cat at stake, Winnie the Horse Gentler, now a senior in high school, and Catman Coolidge will have to join Hank, bringing Nickers and everything they've got to save Starlight Animal Rescue.
Starlight Animal Rescue: Where problem horses are trained and loved, where abandoned dogs become heroes, where stray cats become loyal companions. And where people with nowhere to fit in find a place to belong.