Owen Baker (Liam Aiken) is a lonely 12-year-old boy whose renovator parents (Molly Shannon, Kevin Nealon) are in the habit of compulsively moving each time they work on a different house. An unlikely friend for Owen arrives in the form of Hubble (voiced by Matthew Broderick), a terrier dog from outer space who has come to make sure all the earthling dogs are upholding the dignity of their royal, other-planetary roots. At first Hubble is repulsed by the behavior he encounters from the neighborhood dogs, but, with the help of Owen, soon learns the value of devotion and love between animals and their human owners.

"Good Boy!" is harmless cotton-candy fluff that is bound to amuse undiscriminating younger viewers, but pales when placed next to al l the similar movies it is shamelessly derivative of. For proof, 1982's classic "E.T.: The Extra-Terrestrial" was the heartfelt story of an alien and a boy who formed a powerful friendship; it told its story with genuine humor and realistic human emotions, and did not pander to any one age demographic. Replace a conventional alien with an alien dog, add more fart jokes than you can count, and out comes "Good Boy!," which goes so far as to steal the same Uranus joke "E.T." had. In fewer words, "E.T." was smart, imaginative, and incendiary. "Good Boy!" is inconsequential and dumbed-down.

Where the picture's main failing falls, however, is on the relationship between Owen and Hubble. For one, it is not developed enough to win you over in the end like it wants to, and two, their friendship feels more like a plot requirement than a believably natural progression. As for the science-fiction aspect, in which the Earth's entire dog population is threatened by the tyrannical Greater Dane (voiced by Vanessa Redgrave), it falls flat and adds nothing to the proceedings.

Liam Aiken (2002's "Road to Perdition") is likable enough as Owen Baker, particularly garnering some nice, quiet moments in the second half, but he is occasionally asked to mug for the camera in a way that he is too old for. In a less showy role than she's used to, the very funny Molly Shannon (2003's "The Guest") adds warm maternal support as Mrs. Baker. In the dog-voicing department, Matthew Broderick (1999's "Election") is fine as Hubble and, standing out, Brittany Murphy (2003's "Uptown Girls") is a quirky delight as the eternally nervous Nelly.

"Good Boy!" is passable entertainment for the under-10 crowd. Its heart is in the right place and there is some cute interplay be tween the dog characters. At the same time, a true quality family film demands much more than simply repeating story ideas and basic dialogue exchanges from previous, superior movies. "Good Boy!" ultimately lacks the three-dimensionality and magical charm that are necessities of achieving this very feat.