Thousands of years ago dogs were sent to Earth to spy on the human race in preparation for a full-scale invasion and take-over. However they have all forgotten their mission and Canid 3942 [voiced by Matthew Broderick] is sent from the planet Sirius to investigate. Canid meets Owen Baker [Liam Aitken], a young boy who provides a dog-walking service. Owen renames Canid as Hubble and the two become friends. Hubble asks Owen to help him get the dogs on Earth into shape before the Great Dane arrives to inspect them - because if they fail the inspection they will all have to leave Earth.