It's no mystery why the Olney Theatre put "The Crucifer of Blood" into its annual murder mystery slot: Zestfully directed by playwright Paul Giovanni, this stylized spoof of Sherlock Holmes is a purple potboiler, bubbling over with mayhem, melodrama and fondly remembered moments from B-minus movies.

The imagination and wit in "Crucifer" puts the recent, more expensive (and, most inexcusably, more predictable) "Sherlock's Last Case" to shame. The show is just about perfect for the Olney, too, crammed as it is with the kind of lush lines that excuse -- even encourage -- the overripe acting that is a staple of the summer theater.

Adapting freely from "The Sign of the Four" and other stories by Sir Arthur Conan Doyle, Giovanni cuts and pastes characters and plot twists from Holmes' extensive casebook, which lends itself handsomely to dramatic adaptation -- "Crucifer" is one of 53 plays based on Holmes and Co.

We first encounter the great detective lolling listlessly about his flat at 221-B Baker Street. Depressed without the mental stimulation of an unsolved crime, he indulges, under the disapproving eye of Dr. Watson, in a spot of his famous "seven percent solution" of cocaine. Watson tries to engage Holmes with a conundrum, which he quickly disposes of. But soon there's a knock at the door. A beautiful, distraught young woman enters, faints -- and we're off.

It would spoil the fun to divulge the details -- that's against the rules -- but I can tell you that it begins with a prologue in India and includes a blood oath, a cursed treasure, an opium den, deliciously florid lines like "Certain things are not known to those who eat with forks," and the vision of Dr. Watson in love.

Martin LaPlatney, who made his Broadway debut in "Crucifer" at the Helen Hayes Theatre, makes a fine Holmes; his sharp, patrician features even resemble the original Strand Magazine illustrations by Sidney Paget. LaPlatney's voice was made for snapping epigrams and withering insults, and he shows us Holmes' flaws as well as his extraordinary assets. Along with the supersleuth's comically clinical omniscience, his genius for minutiae and express train of thought, we see his vanity and egocentric impatience.

His sidekick Watson is, by definition, a blander creature and something of a wet blanket, but Gavin Troster doesn't do the character justice. His stuffy Victorian attitude is about right, but it's delivered with a distractingly belabored enunciation. Valerie Leonard lends damsel-in-distress Irene St. Claire her precise diction and porcelain features. As played by James Lecesne, peg-legged cipher Jonathan Small seems to have wandered in from a Robert Louis Stevenson story. William Verderber provides an enjoyably over-the-top turn as Maj. Alistair Ross, a decadent old dragon whose hysterical shrieks are inevitably answered by thunderclaps.

Giovanni captains the merry chase with appropriate excess, and adds a hilariously portentous "sound track" of baying hounds, ghostly choirs and sawing violins.

The set is lavish by Olney standards, as designer Robert Klingelhoefer produces five exotic locales, including a dusty Indian fort, Holmes' sepia-toned Baker Street study, a gloomy, Dickensian miser's mansion, an ornate Oriental opium den and, most amusingly, the River Thames on a foggy night. There are some shortcomings in the lighting department, and opening night was marred slightly by slow set changes and a handful of minor technical gaffes. But then, it's a dauntingly complex production, and surely the Olney's backstage crew will soon find the demands of this confounding and criminally comic play . . . elementary.

The Crucifer of Blood, by Paul Giovanni. Directed by Giovanni; settings, Robert Klingelhoefer; lights, Richard Schafer; costumes, Diane Fargo. With David Conaway, Adam Graham, Seth Jones, Martin LaPlatney, James Lecesne, Valerie Leonard, Wayne Robinson, Kyle Shannon, Gavin Troster, William Verderber, Ralph Williams, Phillip Wong. At the Olney Theatre through Oct. 18.