A THEATER COMPANY whose goal is "to provide affordable options to people who might not or could not otherwise attend live theater" is something of a novelty in an industry which often seems glutted with narcissistic, inflated personalities. You know the wisdom: "Show business is show business, baby--no business, no show."

But Theater at the Square, through the Cambridge Acting Company, has committed itself to providing entertainment which is very professional, and refreshingly affordable. The Victorian suspense thriller, Angel Street, is being held over through this week, and ran ks as the best entertainment buy in the Boston area (next to the Red Sox, of course).

The best way to approach a Victorian suspense thriller is with complete irreverence: take advantage of Theater at the Square's "dinner-theater-parking" package and the Hyatt Regency's Spinnaker Lounge for some drinks (or anywhere else you want to drink) and snucker on down to the Hasty Pudding Club, where the company is making its summer home. This effect will not only increase the drama of the drama, it will add a humorous dimension to the production. Which finally brings us out of this digression: the only touch Angel Street needs to become a better thriller is a dab of comic relief.

The entire story takes place in a staid Victorian parlor an Angel Street, London, in 1880. Gas lights, spats, hand-kissing, penis envy and everything. Mr. Manningham (Edward Kaye-Martin) is tormenting his lovely Victorian wife (Innes McDade) in those early scenes, trying to convince her very subtly that she is going insane. Of course, in Victorian England, nothing could be worse than being called crazy. And how does he do it?

He takes a portrait off the wall and hides it behind a cupboard and when his wife enters the parlor, Mr. Manningham authoritatively interrogates her on the whereabouts of his missing painting. Getting frantic and confused, Mrs. Manningham admits that she must have hidden the thing, quite unbeknownst to her own conscious mind. Mr. Manningham's conclusion is that she must be crazy.

Big deal, you think? Well, just try to remember that this is Victorian England, and the entire ambiance of constipation is no coincidence. This aptly illustrates the play's only shortcoming--the wan sense of humor in the early scenes. Innes McDade's Mrs. Manningham is believably portrayed throughout the production, but during that first scene, it is astounding how easily she is made to cry and wail and grovel and admit that she is crazy. A little temperance would have been as welcome as a sedative in the Fenway Park bleachers.

Kaye-Martin's portrayal of the master of the house was not masterful, but good--he had the job of portraying the banality of evil in a high-faluting style, but overdid the banality a bit. He rants and demands and insults with all the consummate evil of Bella Lugosi and Martin Bormann fused; Kaye-Martin overplays his role just so much, just so much that despite his overkill in the sexist-megalomaniac-asshole department, the crowd still takes his character seriously, according his work with all of the hisses and spittoons given the villain in any old time movie.

But even Mr. Manningham can't be all bad. And even Mrs. Manningham can't be all that ridiculous. The way these two work themselves up over misplaced painting and lost grocery bills is really silly. Indeed, she is so neurotic and he so didactic that the couple resembles an unlikely marriage of Diane Keaton and H.L. Mencken.

BUT THE COMIC relief comes never too soon in the person of Rough (that's right), a feisty and eccentric ole London detective, who sweeps in with a bottle of Scotch whiskey and the story of an ancient crime commited right in Mrs. Manningham's parlor. John Guerrasio brings the play to life with his odd characterization. Mrs. Manningham settles down, Mr. Manningham's motives are revealed, and Rough sprouts about the stage with his Holmesian moustache and pipe, becoming both the saving touch of credibility to the play, but also the final measure of mystery that escalates this belated tale of Victorian constipation into something of an adrenalin surge.

As Mrs. Manningham hides in her room with a headache and her servant, Nancy (Wendy Meri Borow) seduces Mr. Manningham, Rough discovers the reason for Mr. Manningham's hostile posture towards his wife. And finally, just finally, this thing gets interesting.

After teetering on the brink throughout the play, neurosis becomes psychosis, and the characters' stereotyped personalities are shattered. McDade's seemingly whimpering, neurotic housewife turns into a ruse; she stalks in circles around her husband, who is tied to a chair in the middle of their parlor. "Come on, cut me loose," he says, as she alternately cackles and cries, gripping her dagger and trembling badly....

It's your responsibility to figure out the rest of it. You've gotten this far. If you're interested in spending your money on "good causes," Theater at the Square is no doubt a good cause. It is a non-profit charitable public corporation (nice combination of words) which offers a theraputic arts program for normal and handicapped children. They were the first such corporation to be awarded a service contract under the Massachusetts Educational Act and they have also received recognition from the United States Commission on Arts for the Handicapped.

Angel Street managers to be a nice trip, taking you back to the good old days when Bedlam was probably the most interesting place in the English-speaking world. And in contrast to today's apocalypse of drugs and free sex and other anti-Victorian diversions, a glimpse of Angel Street will teach you to appreciate your sanity