All theater depends on a collusion between stage and audience, an implicit agreement to suspend disbelief and enter the world of the play. The best theater invites you to imagine, to leap from the mere suggestion of a concept to the full realization of it in your mind. The simple act of comprehension makes you feel delighted with yourself; something widens in your thinking. Dutch director Moniek Merkx makes the game of engaging in her dip into the Grimm Brothers' fairy tales in Once Upon a Forest at the Children's Theatre Company irresistible.

Merkx hooks you into her game from the moment the lights go down: a red plush curtain hangs two feet above the stage, and female white-stockinged legs dance across in procession to Victor Zupanc's recorded music, each pair in perfect time. Soon, they seem not like actors' legs, but like puppets. Then a male pair of legs appear that doesn't know the steps. Dragon's feet clump beneath the curtain. Dragon feet and novice male dancer legs meet. There's a hungry roar. Male legs tremble, are yanked upwards ... and eaten?

In a second sequence with the curtain, the remarkable legs manage to tell the story of Cinderella.

Forest, developed by Merkx and Elissa Adams in CTC's new play lab, doesn't set out to tell fairy stories in a traditional fashion. This is a medley of Grimm stories, with fragments of Snow White, the Brave Little Tailor, Hans My Hedgehog, Dummling, the King's Youngest Daughter and Cinderella, giants and a fire-breathing dragon. And fleeting references are made to Little Red Riding Hood and Repunzel. All of the characters are played by the eight-member ensemble, who venture into the scary forest and help to tell each other's tales.

Merkx signals a childlike approach to Forest early on. In the scene following the legs, the ensemble argues like school kids over who should play Snow White. They settle the matter with Eenie, Meenie, Minie Mo. The whole production has the spontaneity of imaginative children at play, where one game slides into another, and where, if you don't have what you need to tell a story, you make it up on the spot.

The ensemble snaps scissors to make an appropriate orchestra for the tailor, who is played by Luverne Seifert. Autumn Ness as Snow White clips into her costume on stage, background owl hoots and dog howls are made in full view by fellow ensemble members. To create a fire, someone lights a match, they all lean in as it gutters, then a small circle of orange light begins to grow, you hear the sound of flames crackling and presto, a fire. Merkx depends on you to imagine the proportions of an unseen giant, once you've seen the three enormous candies he drops on stage. And, when she needs to bring two giants on stage, she simply upends the rules and shrinks the tailor to a look-alike puppet and reduces the massive tree trunks of Sanne Danz's simple forest set to a miniature version, represented in a portable see-through box. In one of the play's most creative tricks, Merkx turns full-sized ensemble members into seven convincing dwarfs.

Among the characters, Reed Sigmund charms as the simple and unloved Hans My Hedgehog, and costume designer Laura Crow has created a wonderfully spiny hood for him. Another charmer is Dean Holt as the ingenuous Dummling. Both characters show that being a good person has its rewards and, with its cooperative storytelling and the ensemble's combined effort to vanquish the dragon, Forest quietly promotes team work.

In keeping with the nature of the play, Crow's costumes are generally simple, as is Danz's set. But, like the play, the deceptively simple set packs a surprise when the characters move into the woods. Geoff Korf's lighting and Joop van Brakel's sound design play an active role in creating the on-stage magic that sets your imagination in motion.

Using simple techniques that will be familiar to some Twin Cities audiences from In The Heart Of The Beast and Theatre de la Jeune Lune productions, Merkx creates stage magic that is transparent, playful and absorbing for almost all age groups. Just a few minutes into the play, you find yourself so engaged in her clever mode of storytelling that understanding comes as quick as turning a page.

Once Upon a Forest runs through March 8. Wednesdays through Saturdays, 7:30 p.m. Some Saturdays and all Sundays 2 p.m. and 5 p.m. $9 -$28. Children's Theatre Company, 2400, Third Avenue South, Minneapolis. Call: 612-874-0400. Online: www.childrenstheatre.org.

Be sure to check the current schedule for theatre in the Twin Cities area

- Elizabeth Weir