If you think Cinderella and her handsome prince live happily ever, if you believe old bean-stalking Jack escapes scot-free after stealing gold and murdering a giant, you are in for a rude awakening, kiddo.

Fairy tales can be awful user’s manuals when it comes to navigating the tangled woods of love and life. No one knows that better than Stephen Sondheim and James Lapine, the Broadway titans who devoted their 1987 musical to exploring the darkness and danger lurking in the shadows of the familiar tales by the Brothers Grimm.

“Into the Woods” opens the 10th-anniversary season for Alliance Theatre artistic director Susan V. Booth. Featuring an ensemble of young musicians who play the delicate score like seasoned masters and an opulent design scheme that imagines the enchanted forest as a gnarly play-scape of the mind, the production is a full-out, 17-member, Broadway-scale extravaganza aimed at audiences 10 and older. A visual knockout that won’t disappoint, the text is also a cluttered, long-winded psychological treatise that for better or ill rarely resorts to the kind of glib, easy answers that are the usual terrain of musical comedy.

But hey, that’s Sondheim! And by the composer-lyricist’s normal standards, this borders on Sondheim Lite. In trying to straddle the line between thinking man’s musical and family entertainment, “Into the Woods” drags on its own repetitiousness and lack of focus. It’s quite a densely crowded forest, too. Among others, we've got Cinderella (Jill Ginsberg), her Prince (Hayden Tee) and her evil stepfamily (led by Chandra Currelley). Also: Rapunzel (Jamie Wood Katz), her Prince (Corey James Wright) and the Witch who wants to be her mother (Angela Robinson). And then there’s Little Red Riding Hood (Diany Rodriguez) and the Wolf (Tee);  Jack (Jeremy Wood), his mother (Courtenay Collins) and his cow; plus the Baker (Mark Price) and his wife (Courtney Balan), characters created by the authors to connect the dots.

In their quest to have a child, Mr. and Mrs. Baker go on a scavenger hunt at the behest of the Witch. Their collision with the other characters constitutes Act I and is apparently meant to unify the narrative threads but never quite succeeds. The less satisfying Act II seems to exist to make the point that nothing ever turns out the way you want, so careful what you wish for. But it sure takes forever to say it. (The show is 2 hours, 45 minutes long, including intermission.)

As a group of supporting players, the cast is mostly strong, a bit green in places, rarely stellar. That said, Rodriguez is a delightful Little Red Riding Hood. Tee and Wright are excellent singers who convey the regal manners of the royals, and Tee makes for a delightfully sinister Wolf. While Balan, Price and Ginsberg all sing beautifully, Atlanta veteran Collins seems to have shredded her voice and can’t quite scale the heights of her material.

Besides the youth orchestra, the true star of this endeavor is Robinson, a striking beauty who spends a good bit of her time hidden in the Witch’s costume. Designer Lex Liang imagines the crone as a pile of misshapen sticks with crooked fingers and protruding branch-antlers. Robinson’s voice sounds otherworldly, formidable and ancient. Just as Judge Turpin imprisons Johanna in “Sweeney Todd,” here the Witch locks up Rapunzel, and their tender moments are among the show’s most moving.

As imagined by set designer Todd Rosenthal, the stage is an enormous sawed-off tree surrounded by an overarching network of tree-house whimsy and arboreal aberration. Liang’s creations are generally stunning, though as a trend, the steam-punk look seems to be running out of, well, steam. And the costume for Cinderella’s mother (nicely played by Barbara Marineau, who also provides the voice of the Giant) seems to have been grabbed off the “Christmas Carol” rack.

“Into the Woods” is that theatrical rarity that attempts to combine aspects of Disney and Ovid, Bruno Bettelheim and Freud. Lapine’s book is an elegant conceit that eventually gets lost in its own cleverness, yet Booth delivers a solid and impressive show that finds the music and comedy in Sondheim’s primal puzzle. Now, if only that cow could dance.

Theater review

“Into the Woods”

Grade: B

7:30 p.m. Tuesdays-Thursdays. 8 p.m. Fridays-Saturdays. 2:30 p.m. Saturdays-Sundays. 7:30 p.m. Sundays. Through Oct. 2. $25-$65. Alliance Theatre, 1280 Peachtree St. N.E., Atlanta. 404-733-5000, alliancetheatre.org

Bottom line: Solid Sondheim.