The Saga of Gus, the Ghost-Face Dog — Susan Mitchell

Saga is the fourth book in the Gus the Ghost-Face Dog Series. Cousins spend their summer vacations and holidays at their grandparents' ranch in the Texas Hill Country with their dogs. Gus is a Blue Heeler and Luke is a Yellow Labrador Retriever. In the first story, Ethan, Logan, Elyssa, and their cousins, Cal and Cara travel back in time. Ethan and Cal are captured by Comanches, and it is up to their siblings and cousins to rescue them, with the help of their dogs. In the second story, Ethan and Cal find a treasure map buried in a cave and search for the treasure which turns out to be on the ranch. In the third story, Ethan and Logan find a lost gold mine which is dangerous and ready to collapse.