From the distant Sirius (AKA the "Dog Star"), an invasion of Earth has been planned for thousands of years now, as canine spies are sent to gather information to prepare for the coming attack. With none of their agents reporting back, the Sirius military sends their best dog, Canid 3942, to Earth to find out what's going on... and soon after landing, he finds himself befriended by a human boy, Owen, who runs a neighborhood dog-walking service. With the "Great Dane" on her way to inspect the troops, it's up to Canid 3942 and Owen to snap the dogs in his area back into shape, or all the dogs on Earth will be recalled back to Sirius for rehabilitation... and man will lose all of his best friends.