Ever since Robby's father was killed while on police duty, Robby has been angry and alone. His father's old partner, a police dog named Marlowe, suffers the same fate. So when Robby sees Marlowe alone and locked up in a cage he begs his mum to let him have him. Instantly, the two are best friends. But, being a cop dog, when Marlowe, sees two familiar criminals in the woods