With years of success establishing a franchise of interactive murder mystery shows across the Valley, The Mystery Mansion Dinner Theatre is back with a new one, “Murder at Magic Manor,” in Scottsdale.

Written by Patricia Harris Smith and directed by Tom Blackwood, “Magic Manor” sports the usual Mystery Mansion formula — gobs of interactivity; Jim Trapani in gleeful drag as another homely, bubbly gal; and enough cheesy, campy humor to stretch across a three-course meal.

But despite its title, “Magic Manor” just doesn’t have the same ol’ magic.
With Trapani, Gary Caswell is a comic linchpin in all of Mystery Mansion’s shows, and here he finally gets the lead as The Mostly Magnificent Steve, a wacky man of illusion — think Vegas mainstay The Amazing Johnathan whose curious string of disappearing female assistants, a list that threatens to grow as long as that of Spinal Tap’s drummers, forms the crux of the mystery.

Caswell’s always been at his best letting his characters exude a flirtatious, slightly perverted edge. There’s the swashbuckling movie hero Edward Manly III of “Murder at Greystone Manor,” quick to accost a female audience member. In “Murder at Bedside Manor,” there’s Little Dicky Slimmons — a wry ode to America’s favorite ambiguous, hyper fitness guru — ever on the cusp of showing a little too much beneath those workout shorts, and Steve Irwin wannabe Dr. Jack Dingo, flirting from table to table with a puppet crocodile cradled in his arms.

In “Magic Manor,” Caswell lets his inner perv fly as loose as his cape, auditioning a bevy of new assistants who have shown up at a gathering of booking assistants (that’s us, playing along): There’s the mousy Marsha (played by Barbara Ellis), the attractive Inge (Kristen Kay Caldwell) and the homely Trick-Zee (Trapani, sporting a foam-padded bust under a wild burlesque getup), and it isn’t long before Steve is sending them through a few of his favorite tricks, including a rather sexist “makeover” machine from which poor Inge returns not made over but knifed in the back.

What follows is a show that sticks largely to the Mystery Mansion routine. The actors themselves serve a standard-fare chicken dinner and chocolate cake dessert for tips, audience members are asked to guess whodunit and, just as the show hits its homicidal heights, folks are brought on stage to perform goofy acts like talent shows — or, in “Magic Manor,” a lame hypnotism bit.

But there’s a zany spirit missing from Smith’s script, which doesn’t zing with the same comic pace of “Greystone” and “Bedside.” Except for Trapani’s rampant drag romping, the ensemble supporting Steve isn’t given much of anything amusing to do, and their jokes — including a lazily recurring bit about “The Brady Bunch’s” Marcia Brady (“Marcia, Marcia, Marcia!”) — are as bland as the veggies served up with dinner.

That’s too bad, as are the close-up tricks the cast performs during dinner breaks: Prop gags we’ve all seen before, with ta-daas as amazing as watching a stain-removal infomercial.

Audiences would be better off waiting until Saturday nights, when Kam’s hosts “Bedside,” a weird, nonsensical hodgepodge of pop-culture references and improvised moments that still, after three years running, sparkles with silly wit.