"Cirque du Soleil — Quidam," which opened Thursday in Blaisdell Arena, has a thread of a story to follow if you know it exists, but it’s the specialty acts — in short, the seemingly impossible feats of flexibility, agility and gymnastic prowess — that give the show its "Wow!" factor.

The story is about a young girl named Zoé who slips into an imaginary world full of colorful characters. The most notable is a mysterious emcee named John; he’s a multitalented and instantly engaging guy reminiscent of Pee Wee Herman and Fishbone vocalist Angelo Moore.

There’s also the Target, featured prominently in ads for the show, who flits and sometimes flies through the story like a cheerful free spirit. A third, Boum-Boum, is earthbound and somewhat menacing in a vague way; he wears boxing gloves and causes thunder and lightning when he hits them together.

The "Wow!" kicks in early with "Diabolos," a segment in which four women juggle large wooden spools on relatively short lengths of rope. OK, we know these women are world-class professionals, but as they toss the spools ever higher in the air, and the four-way routine becomes increasingly complicated, there’s still the breathtaking sense of "I hope it works."

It does, in grand style.

Then there’s "Hand Balancing," a solo performance in which a woman moves gracefully through a series of physically challenging poses — many while balanced on one hand. "Statue," performed by a man and woman in minimal flesh-toned costumes, is a series of mesmerizing feats of strength and balance. Both acts earned several rounds of spontaneous applause during their performances. It was applause well earned.

"Banquine" closes the show bigger still with a troupe of 15 performing spectacular acrobatic routines.

Anyone involved in competitive cheerleading should be sure to see the finale this group executes. There’s a moment when it’s suddenly clear what they’re setting up to do — and then they do it in dramatic style.

There are spectacular aerial acts as well. "Aerial Contortion in Silk," performed by a soloist earned applause while it was still in progress. "Aerial Hoops" has three women in beautiful costumes hanging and dangling and spinning with dexterity and grace. Thick ropes provide the performers’ working medium for "Spanish Webs" as five aerialists — two women and three men — perform in various dramatic combinations.

The Clown — Toto Castineiras — stars in two old-school audience participation sketches. Both were big hits with the audience on opening night.