DURHAM - In a moody American Dance Festival program that explores shadowy recesses of the psyche, Pilobolus reveals invigorating glimmers of light.

The program, which opened to a packed house Thursday, is anchored by the ADF-commissioned world premiere of "Darkness and Light," a shadow play that takes the veteran troupe's popular morphing silhouettes seen on car commercials and expands the technique exponentially.

After revealing its hand by exposing the dancers and their various lighting implements in a teasing tableau, the troupe disappears behind a giant white screen, promising the shadow puppetry that this collaboration with puppeteer Basil Twist has led fans to anticipate.

But who could expect the kind of images that appear on the screen soon afterward -- amorphous creatures that shudder, float and jolt like specimens on a microscope slide?

How the dancers achieve this is anybody's guess, which for some fans will add to the intrigue while others may lose interest. It looks initially like a screensaver or a film from a planetarium light show, and one fan confessed afterward that he had presumed it was a film. Where's the live magic in that?

But then bodies reappear, as they did briefly at the dance's start, torsos expanding and deforming like a rubbery Stretch Armstrong action figure.

Tricks of perspective prompt the audience to think about where they fit into the mix, which ultimately ranges from the jittery cells on up to humans and an enormous being that suggests a grand creator of it all. Thematically and physically, this collaboration expands preconceived notions of what a puppeteer can do.

The premiere is the dreamiest of the program's fare, a toast to the infinite capacity of invention. But even the darker pieces weave hope into their overarching sadness.

With former "Pil" Martha Clarke's achingly beautiful "Nocturne" -- originally created in 1979 -- it's a perpetually dashed hope, as solo dancer Renee Jaworski's character's graceful self-image is crippled by old age. But there's a heart-wrenching beauty in her determined pursuit of lost agility. And it's a haunting reminder of how our nation often dismisses the elderly as faceless shells of people who used to matter.

The new "Razor: Mirror" takes a similarly painful journey. On its surface it appears to be about mental illness, and some audience members might see its dark clownishness as offensively mocking. But if read as a piece about our own faults and fears, and of taking the seemingly perilous leap toward trust, it's far more affecting and, ultimately, hopeful.

"Lanterna Magica," another new work, conjures an enchanted forest akin to "A Midsummer Night's Dream." Fireflies and fairies work mischievous magic, luring their charges through dizzying acrobatic feats.

"Symbiosis," a 2001 piece, melds the company's two strongest attributes -- physical agility and emotional expression -- into a mesmerizing pas de deux that explores the precarious terrain of shared dependence.

Jenny Mendez and Manelich Minniefee perform the duet exquisitely, tumbling and attaching to each other with remarkable fluidity and a superhuman strength that makes it easy to forget that any strength is needed.

The show kicked off with a clever surprise tribute to ADF's 75th year. But this cohesive, stunning program is the real gift to the festival and its fans.