It's hard to imagine two plays more different from Christopher Hampton's "Dangerous Liaisons" and J.M. Barrie's "Peter Pan," both currently on stage at the Stratford Shakespeare Festival in Ontario. The first is a 1985 adaptation of Choderlos de Laclos' 1782 epistolary novel set among a group of decadent, dissolute French aristocrats. The second was originally an Edwardian play for adults, but has come to be a children's classic to which parents may safely take their 3-year-olds. One result of that change was the unceasing refrain from the row behind me, "Mommy, when does Tinker Bell come back? Mommy, when does Tinker Bell come back? Mommy...?"

Although many of the same actors appear in both plays, additional differences emerge almost immediately. "Liaisons" is brilliantly directed and performed. Director Ethan McSweeney and the cast are perfectly attuned to the play's heartless wit. They possess deep understanding but make no easy moral judgments. They let its corruption speak for itself.

"Peter Pan," on the other hand, is a mess. Director Tim Carroll chooses shtick over characterization and repeats tired physical jokes that often fall flat, even with children who have never seen them before - a coat and hat that fall to the floor no matter how often a character tries to hang them up, for instance. And how many wiggling backsides will we have to endure before the final curtain? If there was a saving grace, it lay in the two animals, Nana, the Darlings' dog, played with galumphing good humor and a keen awareness of doggyness by Jay T. Schramek, and the fierce, funny crocodile, an exercise in stage wizardry by a team of actors and designer Carolyn M. Smith. Her sets vary from an unimaginatively ugly hill beneath which Peter and his boys live and hide to a very clever use of stretched blue fabric with long slits to create an ocean that lets people tread water as they hide from the villainous Captain Hook.

"Liaisons" tells a story of seduction, vengeance, cruelty, vanity, jealousy, self-indulgence, and nearly any sin of pride and sexuality you can imagine. La Marquise de Merteuil (the superb Seana McKenna) and her former lover Le Vicomte de Valmont (the equally superb Tom McCamus) seek to seduce young Cecile Volanges before her marriage, and also La Presidente de Tourvel for the sake, mainly, of destroying the reputation of one and the goodness of the other. Sara Topham, who plays de Tourel, is a lovely actress of wide emotional range and justifiable confidence. Valmont agrees to Merteuil's proposals out of his own vanity and his jaded search for novelty, but also claims a night with her if he succeeds. Despite his success, she refuses in the end because her goal all along has been to destroy him.

De Merteuil's eloquent set speech about the way a woman may proceed in this world transforms the play, strangely, into a vivid expression of feminism. Her only weapon is sex, she says, employed with intelligence and cunning. The play ends with her power intact but also with a dramatic (and probably unnecessary) reminder that this world will soon come to a violent end.

Both the content and the imitations of sex make "Liaisons" very much not a play for the young or immature. As for the announcement of "brief nudity," it comes to nothing more than a bare back during a sex scene, as Valmont uses a courtesan as a writing desk to lean on. It's a very funny moment.

The genuinely funny moments in "Peter Pan" are much less frequent, although the director and cast work relentlessly to make the audience laugh. The problem is that you can do the play in at least three ways - as a show for children, no excuses asked for or given; as a fin de siecle exploration of domestic values and the relationships between adults and children; or, in a post-Freudian world, as a dark, dream-like, early Modernist play about life, death, change, and danger. Barrie (1860-1937) and Freud (1856-1939) were virtual contemporaries. But director Carroll never decided which "Peter Pan" he wanted to do, resulting in a frenzied whimsy that veers back and forth as if it doesn't know where it's going or why it's going there.

Although an adult actress usually plays the part of Peter, the boy who refuses to grow up and enter the world, it is always interesting to watch a male tackle the part. In this production, Michael Therriault gives us a Peter on uppers; his nonstop energy is much too mannered. He never steps when he can leap, never talks when he can yell, never points when he can throw himself at whatever's there. His energy is initially boy-like but eventually empty.

The Darling parents (Laura Condlin and Sanjay Talwar) are alternately loving and pompous although they and the charming Sara Topham as Wendy are sometimes hard to hear, partly because the six children seated near me weren't especially interested in them. Wendy's brothers and the boys who follow Peter offer little but a lot of energy. The director also replaced the Indians of the original with four Amazons, in a craven nod to political correctness.

The Stratford Shakespeare Festival

Through October 31

Stratford, Ontario, Canada

800-567-1600, stratfordfestival.ca