In notes for its production of "The Sign of Four," the Round House Theatre takes pains to point out that the script, written by John Edwards, has been taken almost verbatim from the novel by Sir Arthur Conan Doyle.

That is meant, no doubt, as reasurance that there's been no tinkering with the goods. In fact, it suggests that very little has been done to turn the novel into a play. At the Round House, we are still very much in the presence of a story told, not a story dramatized.

Naturally, Dr. Watson is along as a foil for Sherlock Holmes, that master of ratiocination. Watson also provides narration between, and sometimes right in the middle, of scenes. Much of the time, it's narration of a curiously superfluous sort.

He tells us, for instance, that a heavy step was heard ascending the stairs, when we ourselves can hear the offstage clump-clump-clump perfectly well. He informs us that "a surprised and startled look" came over Holmes' face, as if Holmes' face, in the chiseled features of Edward Trotta, weren't right there for all to see. At one point, he even passes on the information that "I looked out the window," then walks to the window and looks out. In each case, it's the novel that's still doing the talking.

Granted, Watson's narrative gifts do come in handy for the climax of the mystery, which consists of a steamboat chase on a fog-bound river. Although several seasons ago a Broadway production based on "The Sign of Four," but titled "The Crucifer of Blood," managed a persuasive river chase on stage, the tiny Round House forgoes the spectacle. The actors act what they can and Watson fills us in on the rest. Meanwhile, those full-blooded scenes that pit character against character and generate real dramatic tension wait to be written.

The production, designed and directed by Douglas A. Cumming, relies on a unit set, slide projections and a few pieces of furniture rear-ranged periodically to indicate the changing locales. Cumming and his cast are able to evoke a coach ride through the London streets quite nicely and they can conjure up the fetid atmosphere of the docks. Mostly, though, the staging is not quite imaginative enough to compensate for the sparseness of the scenery.

Without spilling too many beans, it can be said that "The Sign of Four" involves a treasure pilfered from an Indian potentate; a troubled young lady, who's been getting pearls in the mail ever since her father disappeared; a strange brotherhood; a blow gun, and rigor mortis. Holmes has no difficulty putting together the pieces, but takes his good time sharing the explanation with others, which accounts for what suspense there is.

Trotta hasn't tried for much of an English accent, but otherwise makes a presentable Holmes, with an emphasis on the dark side of the character, who takes drugs to relieve his boredom. Gerry Paone is a likable Watson, veering toward the puppy dog, and the dependable Greta Lambert is pleasant as the distressed damsel. Michael Littman contributes a properly scruffy villain and, for what it's worth, boasts one of the more unusual wooden legs you're apt to see on a stage.

Still, something's wrong and it's not just the perfidy of greedy men.Here we have a stageful of actors, exchanging words, making gestures, simulating passions, yet "The Sign of Four" leaves you with the disquieting impression that you are really being read to.

THE SIGN OF FOUR. Adapted by John Edwards from Sir. Arthur Conan Doyle's novel. Directed by Douglas A. Cumming; sets, Douglas A. Cumming; coslumes, Kale Cowart; projections and lighting, Richard H. Young. With Gerry Paone, Edward Trotta, Greta Lambert, Mark Jaster, Michael Littman. At the Round House Theatre through Feb. 6.