I was sitting in the audience of the Young People's Theatre in Toronto with 468 fifth-graders. We had just seen the first act of ''The Mystery of the Oak Island Treasure,'' and were watching the sets being changed as we waited for the thrilling conclusion.
The little red-haired girl behind me was pretty sure she knew what would happen when the mother and the professor got back and discovered that pirates had made off with the children, so I asked her if this was the first play she'd been to. ''Oh, no,'' she said. ''I've been to four others.''
To judge from a week I spent going to plays in Toronto this month, fifth grade is none too soon to get started; there's a lot to see here.
And if you're a traveling theater maven, Toronto might be a good place to go for a modest Canadian theater blitz.
David Matthau of the Nederlander Organization says he never goes to Toronto looking for plays to produce in New York because Canadian theater is too, well, Canadian. But that, according to Peter Moss, artistic director of the Young People's Theatre here and former assistant artistic director of the Stratford Festival in Stratford, Ontario, is one of the virtues of Toronto theater.
''There's no money in it, there's no fame in it, there's no status in it, there's no movie contracts at the end of it, there's no Broadway contracts, there's simply work for its own sake,'' he says. ''You have to bring to it a kind of enthusiasm for the work that you're doing,'' since it probably won't go to New York. ''I think that's the thing that distinguishes Toronto from any other theater city . . . of this size.''
Though there's little that's Broadway-bound here, the city's got Ed Mervish, the Toronto entrepreneur who just bought London's Old Vic. He's restored Toronto's Royal Alexandra Theatre and put it back in the black with touring shows from London and New York. But, basically, this is a town to go to for smaller, thoughtful productions.
Alexander Cohen, the New York producer who is doing the Peter Brook ''Carmen, '' had fond memories of Toronto, where he supervised the opening and booking of the O'Keefe Center, a 3,200-seat auditorium, in 1959. Three years of booking the center, he said, ''demonstrated that Toronto has an enormous theatergoing public if you've got the product to go into it. Shows of mine play there all the time (''A Day in Hollywood/ A Night in the Ukraine,'' and Liv Ullmann in ''Anna Christie'').''
They have done well, and he is looking at one or two Canadian plays for production in New York. ''It's a fertile arena of theater. It's a cosmopolitan, metropolitan center with the right demographics, and a lovely, lovely place to be.''
My recent week of playgoing yielded two unforgettable plays, a disturbing one , a variety of intriguing ones, and a deep regret that there are only seven nights and a matinee or two in a week. All visits to the theater were engrossing. Two plays mentioned the same Chinese restaurant in town, which gives you a feeling of coziness, if not universality. Only one play, ''Mousetrap,'' wasn't Canadian.
This is no big deal, according to Peter Moss. ''Most of us just do Canadian plays,'' he said. ''We stopped making a feature of it. Nobody in the States bills them as American plays. There was a period in which the thought of doing Canadian plays was crazy. . . . They used to go, 'New Canadian plays,' which was (like saying) 'Look out, duck!' or, 'Maybe you don't want to come to this'; an apology.
''Now, nobody bothers. New plays is what the Tarragon (Theatre) does. Some of them are British, some of them are American; you can't tell the difference.''
The Tarragon is, as a Toronto theatergoer explained, ''in the alternative mainstream.'' It's a small, well-designed theater a little north of downtown (30 Bridgman Avenue, telephone (416) 531-1827.)
''Tower,'' which just closed there, was Lawrence Jeffery's elliptically written play about ruthless businessmen. Donald Davis, a Canadian actor, was brilliant as a charming brute who practices golf shots as he plots a partner's demise. Marion Gilsenan played the partner's widow with equal intelligence. But her fey, warmhearted character proves to be more than a match for the abstract cunning of the businessman in the shocking last scene.
Beautifully set on the theater's thrust stage, this Canadian play would have been striking in London or New York. It takes place in a modern office tower, but the final conflict between tycoon and widow brought Antigone to mind.
Although ''Tower'' has closed, its quality and the Tarragon's reputation would put this house on any theatergoer's itinerary. ''The Farewell Heart,'' by Charles Tidler, which runs through Jan. 1, takes place on a small, hippie-inhabited island off British Columbia in the '70s and is described as ''a comedy that ends tragically.''
Salome Bey wrote, composed, and stars in another memorable play, ''Shimmytime!,'' at the Basin Street Cabaret (180 Queen Street West, telephone ( 416) 698-2277). As Ethel Waters, she sings the story of that jazz performer's career through songs like ''Stormy Weather'' and ''Am I Blue?'' as well as her own ''Shimmytime!''. The play is presented in a cabaret setting, with a team of excellent dancers who become other characters in Ethel Waters's life.
Salome Bey moved from New Jersey to Toronto in 1964 when she married a Torontonian. She has taken detours to the Kennedy Center in Washington in ''Don't Bother Me, I Can't Cope'' and to New York for ''Your Arms Too Short to Box With God,'' but she feels Toronto has given her a chance to go beyond the kind of roles she was doing in New York, to write, and to live with her husband and children and still have a career.
''It's the land of hard knocks,'' she says of theater in Canada, with a laugh , because audiences are so reserved. ''By the time you get to New York, you are so together that . . . they're overwhelmed because you've struggled so hard'' to get across to the audience.
''Shimmytime!'' certainly gets through, as the young Ethel Waters survives hard knocks on the black vaudeville circuit, graduates to the Cotton Club, then plays for white audiences. Finally, singing ''I'm Stepping Down, But Looking Up, '' she quits to work for evangelist Billy Graham. Salome Bey has a fine voice. And at the performance I saw, she had the audience in tears and then clapping along with the rousing finish.
Children would enjoy the Young People's Theatre production of ''A Christmas Carol,'' but adults shouldn't miss out on it, either (165 Front Street East, telephone (416)864-9732). YPT puts on family theater, not children's theater, according to Peter Moss. If you aren't traveling as a family, a visit there is enchanting anyway. The audience is so enthusiastic it starts applauding the minute the lights go out.
Well they might be. The performance of ''The Mystery of the Oak Island Treasure'' that I saw was intriguing. The child actors shone. This is the second-biggest theater in Toronto, and it acts like it. The currently running ''A Christmas Carol'' adds weekday matinees during the Dec. 20-31 school vacation time. Jan. 19-Feb. 26 is ''Of Mice and Men.''
At 25, George Luscombe's Toronto Workshop Productions is the city's oldest theater company. It has social conscience. ''Names,'' a play about the McCarthy era, was alternately bright and heavyhanded, and consistently upsetting. ''The Jail Diary of Albie Sachs'' opens Dec. 29. It is an adaptation of the diary of an imprisoned white South African lawyer who fought for the rights of black South Africans in the '60s and '70s (12 Alexander Street, telephone (416) 925- 8640).
Prices for these plays range from $4.80 for the Young People's Theatre to $12 for ''Shimmytime!''. The shows are easily reached by public transportation.
Probably the most pleasant thing for me about going to the theater in Toronto that week was walking home - thinking - through the yellow and toast-colored leaves, between the granite cliffs of insurance companies and the brown brick castles of the University of Toronto.
Toronto playwrights and actors give you a lot to mull over, and this is the kind of place where it's still possible to walk home alone after 10 - as long as it isn't snowing.