Once upon a time there was a boy, a very odd boy, an ugly duckling of a boy. This boy, Robert Lepage, would grow up to be the swan of the international avant-garde - directing Wagner as well as Cirque du Soleil, combining technology with architecture and puppets, each show stranger and more outrageous and more admired than the last.

But the swan, though famous, was still looking for a creature like himself, just as he had when he was an ugly duckling. And finally he found another very odd boy, another ugly duckling who also grew into an international swan: Hans Christian Andersen. Together, with the enormous talent of Yves Jacques, the much-acclaimed (and no wonder) actor who plays all its characters, they created a brilliant, thrilling, funny show. The Andersen Project ends its three-day run at the Merriam Theatre tonight. Drop whatever you were planning to do and go see it.

This theme of doubling doubles itself as Frederic arrives in Paris from Montreal (Lepage is Quebecois), having been commissioned to write the libretto for an opera based on an Andersen story, just as Lepage was commissioned by Denmark to write this show for the 200th anniversary of Andersen's birth.

And in the middle of The Andersen Project, Arnaud - the high-pressure, sophisticated manager of the Paris Opera - tells his daughter a bedtime story, Andersen's "The Shadow." Jacques creates Arnaud as Arnaud creates the story's character, a man whose shadow takes over his life. Then he creates the shadow, and then we become the invisible daughter's doubles as we are mesmerized by the effects created with just a voice and little lamp.

By the end, Frederic's disastrous love life will mirror Arnaud's, Arnaud's obsession with masturbation will mirror Andersen's, and the moral of "The Shadow" will prove true: "Each of us has a dark side and if you let it dominate you, it will destroy you."

Andersen's tale "The Dryad" is about a spirit caught in a chestnut tree who wants to become a human being with "passion and audacity." She appears first as a tiny puppet, and, when Frederic steps behind a tree looking for a dog, he emerges a second later on its other side as the dryad, now transformed into a woman, who then sees the wonders of 19th-century Paris projected before her and our eyes. Then she appears as a marble statue that Frederic kisses in the Bois de Boulogne.

There are effects to dazzle the eye as well as the mind - the dog Fanny becomes a main character though all we ever see is her leash; a dressmaker's dummy "plays" Jenny Lind and is lovingly, erotically undressed by Andersen; porn booths are the shadows of computer stations in a cyber cafe; phone conversations in French are given subtitles as if they were operatic lyrics; a graffiti artist's tag doubles Andersen's initial; and the show we're watching has found a very new, very rich way to tell these old stories.