Superior production values add menace to a story that could have been portrayed considerably lighter of weight. This third outing of the K-9 franchise comes a dozen years after the middlingly successful original and three years after K-911, which did quite well as a direct-to-video release. The third installment lives up to -- and sets a standard for -- the franchise record, with James Belushi and the German Shepard King getting along as naturally as if King really were Belushi's loyal pet. There are human cinematic duos that can't match the charm of these two. The plot is kept sharply focused, but is permitted to stretch its boundaries to develop character in a couple of side-stories that add dimension. There's danger when things need to be dangerous, and there are laughs when things need to be lightened up. In this case, the dog is wagging the tail; K-9: P.I. proves that three's a charm.