“The Mystery of Irma Vep,” through July 14 at the Pennsylvania Shakespeare Fesitval, is too much fun.

That’s for openers. it’s also a fascinating, self-contained, self-proclaimed, compact comedy of manners, and ill-mannered at that, in breaking the fourth wall between actor and audience by using nearly every trick in the book.

When the director is Jim Helsinger, that’s a thick book.

When the actors are Christopher Patrick Mullen and Brad DePlanche, you can be sure they’ll throw the book at each other or, better yet throw out the book. The opening night June 22 performance was seen for this review.

While playwright Charles Ludlum’s parody is not improv, it gives actors and directors great leeway in interpreting the roles. Needless to say, they let it fly. Or, to put a finer point on it, they let it rip.

The plot is goofy beyond belief. “Irma Vep,” an anagram of the word vampire, time-trips through centuries of popular enterainment. It’s rooted in Penny Dreadful tabloid publications of 1830s’ Great Britain, with copious references to Shakespeare lines of dialogue, other books and plays, and classic films, including Director Alfred Hitchcock’s “Rebecca” (1940), starring Joan Fontaine and Laurence Olivier, and Director William Wyler’s “Wuthering Heights” (1939), starring Merle Oberon and Laurence Olivier, and updated through to its 1998 off-Broadway debut. “irma Vep” is so campy, you could pitch a tent.

“The Mystery of Irma Vep,” presented a dozen years ago at PSF with the same comedy trinity (Helsinger, Mullen and DePlanche), somehow seems bigger this time around, again in Shubert Theatre, even if physically it hasn’t changed.

Costume Designer Lisa Zinni has chosen frocks that are even more fabulous. Scenic and Lighting Designer Steve TenEyck has more deeply colorful hues and brighter lighting flashes. Original Sound Design by Matthew Given and Sound Designer William Neal keeps the audience on its ears with plenty of smart starts.

Under Helsinger’s “hellzapoppin’’ direction, combined with Choreographer Stephen Casey, there’s so much going on, and at such a rapid pace, that you’re laughing before your previous laugh subsides.

The actors inject a fair amount of stage business: Mullen’s hand repeatedly gets slammed in a drawer; DePlanche’s inexplicable mispronunciations (tomb becomes “tombah”), malaprops and strange high-pitched staccato utterances.

Each actor plays three roles. Mullen is Jane Twidsen, a maid; Lord Edgar Hillcrest, lord of the manse, and An Intruder.

DePlanche is Nicodemus Underwood, a stableboy; Lady Enid Hillcrest, with a wig that rivals that of the Queen of Hearts on a pack of cards, and Alcazar.

How Mullen and DePlanche accomplish numerous split-second costume changes, as well as character delineation, is beyond me. They throw their talent into each portrayal with abandon and yet they are never out of control. They are over-the-top without being over-the-top, if that makes sense. It’s a fine line, and with Helsinger’s keen guidance, they are masterful.

DePlanche is a genius of the slow take, slow burn, sly turn of phrase and body.

Mullen is a genius of the whip-smart, razor’s edge, sharply-drawn tilt of head, angular body and drop-dead stare.

Did we say there are Mummies? They’re played with gusto by Mackenzie Moyer, Mark Yowakim and Brooke Harrsch (who delivers the best-ever PSF curtain talk). Mummies, dearest.

Don’t miss the fun and frolic that is “Irma Vep.” You even get to keep a PSF “Irma Vep Cheat Sheet” of two pages of insider’s references

“The Mystery of Irma Vep” is how they do it. See it and find out.

Tickets: Labuda Center for the Performing Arts lobby box office, DeSales University, 2755 Station Avenue, Center Valley; pashakespeare.org/psf_tickets.php; 610-282-WILL (9455)