I grade big screen cartoons for kids on a sliding cynicism scale.

They’re all products designed for and marketed to children, and most every studio has a deal with some animation house or other to get themselves a cut-rate piece of that Pixar pie.

The folks who made “Gnomeo & Juliet” figured out a way to make a cheap semi-musical, basically showing British garden gnomes having epic under-sized adventures while Elton John and Bernie Taupin turn Elton’s back-catalog into cash by parking his bubbly ’70s/80s pop-rock at appropriate places in the action.

The involvement of “Rocket Pictures” as producers parks “Gnomeo” and its sequel, “Sherlock Gnomes” somewhere below “Despicable” sequels, and slightly above “Free Birds” and assorted abominations foisted on the under-age public by Harvey Weinstein and others.

It doesn’t have a laugh in it, and the story isn’t worth more than a sentence long summary. London is undergoing mass gnome-nappings, including the clan of Gnomeo (voiced by James McAvoy) and Juliet (Emily Blunt), so the gnome world’s greatest detective, Sherlock Gnomes (Johnny Depp) and Dr. Watson (Chiwetel Ejiofor) are on the case.

Moriarty may be involved.

“Fudge buckets!”

And since Ricky Gervais wasn’t available, Jamie Demetriou takes a shot at impersonating him. 

There’s barely a quotable line. Juliet wants to know, “What are you LOOKING for?”

“An assistant who asks fewer questions!”

But there are two clever visual ideas, so credit where credit is due. The filmmakers took a shot at depicting Holmes’ observation and deduction powers from inside his day-dreamy brain. They’re mimicking what Guy Ritchie did with Robert Downey Jr. This Holmes pieces together his puzzle in his head in black and white Escher-scapes and the like.

The other cute scene? Their quest takes the quartet to Chinatown, where they run afoul of Asian cat garden statuary, porcelain boss, cat statue warriors, etc.  And the voice of the peerless James Hong.

Otherwise, there’s nothing to this for adults, and precious little for kids aside from a disco version of Elton and Kiki Dee’s “Don’t Go Breakin’ My Heart.”

MPAA Rating: PG for some rude and suggestive humor.

Cast: The voices of Johnny Depp, Emily Blunt, James McAvoy, Chiwetel Ejiofor, James Hong, Mary J. Blige, Maggie Smith, Michael Caine, Ozzy Osborne

Credits:Directed by John Stevenson, script by Ben Zazove. An MGM/Paramount release.

Running time: 1:26