Journey's End (The Last Dogs Series #4)

Canine heroes Max, Rocky, and Gizmo return in this exciting series finale! As the trio travel south, following a trail of beacons left by Dr. Lynn, they encounter a stampede of horses. The horses urge the dogs to turn back, warning about a "silver wall of doom" that lies ahead.
But the warning only serves to motivate Max. Could this be the wall from his dreams? The wall keeping Max from his family? Helped by animals along the way -- including bats and armadillos -- the dogs find themselves d...