If you've seen the ads for "Zeus and Roxanne," you pretty much know what to expect from this family picture — a bizarre cross between "Benji" and "Flipper," with nods to "The Parent Trap" and "Homeward Bound."

A benign effort that is occasionally charming — but more often just silly — "Zeus and Roxanne" has a couple of parallel plots at work, laced with pratfalls and a television sitcom sensibility.

The dominant story line has grieving widower Steve Guttenberg, a composer who writes commercial jingles, moving into a summer home across the street from divorced marine biologist Kathleen Quinlan. It isn't long before Guttenberg's young son (Miko Hughes) and Quinlan's two pre-pubescent daughters (Jessica Howell and Majandra Delfino) conspire to push them into romance.

Hughes, by the way, is one of those mini-adults, fixing meals and cleaning up after Dad, who is a sweet, grungy, motorcycle-riding doofus and something of a slob. The girls, meanwhile, are precocious but sweet, though prim-and-proper Mom always fears the worst about their behavior.

The secondary plot, which is far more interesting — albeit a bit off the wall — has Hughes' mangy mutt Zeus following Quinlan onto her boat, then getting into a barking conversation with Roxanne, a dolphin Quinlan is trying to re-introduce into the wild.

Quinlan realizes that the two creatures are engaged in a bit of "interspecies communication" (and some interspecies kissing, as well), which prompts her to fire off an application for a grant to keep her work going.

Meanwhile, her former boss (mean old Arnold Vosloo of the straight-to-video "Darkman" sequels), clumsily tries to sabotage her work, which leads to a comic finale loaded with plot holes. (And, yes, the dog urinates on the bad guys.)

But all of this is really just an excuse to build something around that sequence that highlights the TV ad spots — when, early in the film, the dog climbs onto the dolphin's back and is carried across the ocean. And it does make for a nice visual moment. (And great poster art.)

Guttenberg, coming off "It Takes Two" and "The Big Green," is apparently pursuing this kind of material, but Quinlan, coming off her Oscar nomination for "Apollo 13," deserves better.

And why does Hollywood make children's movies so sappy, sentimental and silly? There are some interesting ideas here that could be explored for clever comedy that would please both the small fry and their parents, if anyone cared.

But as it is, this one should be labeled "For Kids Only." And undiscriminating kids at that.

"Zeus and Roxanne" is rated PG for some comic violence and vulgarity.