Why is the Philadelphia Theatre Company bothering with a trifle such as Ken Ludwig's

Baskerville: A Sherlock Holmes Mystery

? That depends on how seriously you take the whole Holmes franchise. Should Sir Arthur Conan Doyle's stories be saved for presentations that explore their durability? Or left to those who exploit their dated quaintness?

Granted, the original The Hound of the Baskervilles - at least as told in the 1939 Basil Rathbone film - needs some help, if only because of the creaky mystery of why scions of the Baskerville estate in the remote British moors are driven to their death by a giant dog. Even though the package is anything but cheap in this polished production previously seen at Princeton's McCarter Theatre, this retelling inhabits a cheap genre codified by The 39 Steps, in which - at least in the opening production Wednesday night - an old British-setting film is used as a vehicle for physical humor and sight gags as old as the hills.

This particular specimen asks you mostly to enjoy the theatrical wizardry of flowers falling from the ceiling, explosive sound effects, people coming and going via trap doors, and various things coming in from the wings, all with hair-trigger timing.

But most of the Baskerville gags in this production, directed by Amanda Dehnert, barely warranted a single flourish, let alone endless repetition, as they received here. Intentionally, secondary characters have odd, tedious accents and bad costumes.

To his credit, playwright Ludwig gives the characters moments of introspection that give them more context and stronger motivations. As Holmes, the charismatic, animated Ron Menzel shows welcome signs of struggle with a few more plot complications than Rathbone faced.

Watson, Holmes' assistant, here isn't dowdy and bumbling (as was Nigel Bruce in the film) but a young, handsome protégé as played by Henry Clarke. Fine.

But the newest Baskerville heir is American, mainly for the sake of bringing a Texas accent into the mix, though Matt Zambrano, for all the fun he has with the role, wasn't costumed or directed to be a convincing love interest for the alluring Crystal Finn. Adam Green is a superb actor, but had mostly a butterfly net to work with as the villain Stapleton.

For me, the only relief from boredom was charting the production's use of Mahler's Symphony No. 3 as incidental music. The first movement's depiction of the explosive advent of summer is used to heighten the sense of horror to come in the moors. Very clever.

So why can't this particular critic lighten up and go with this tissue-thin comedy? With so much good theater in this town, and limited production money, why take on something that rides on the coattails of preexisting work without respecting it enough to examine why it's still a going concern? Can't we leave dopey stuff like this to TV?

"Baskerville," at the Suzanne Roberts Theatre, 480 S. Broad St., Through Dec. 27. Tickets: $15-62. Information: 215-985-0420 or www.philadelphiatheatrecompany.org.