the Phantom Mirror (Hank Cowdog Series #20) in Bloomington, MN

Pete warns Hank that a stray dog has invaded the ranch and is lurking inside the machine shed. Naturally, Hank goes to investigate, and sure enough, he finds the phantom dog--in an old mirror stored in the machine shed. But then Drover looks into the same mirror and sees a "handsome prince." Holy smokes, it appear that two dogs have invaded the ranch!
This story features two songs: "Poor me" and "Gloria."