A documentary by Stephen Low. Narrated by Ed Harris. Rated general.

You have to admire the determination Stephen Low shows in this IMAX undersea flick. It's not every director who could underplay the search for the source of all life throughout the cosmos, but Low does it nicely, starting not with the wow footage--hi-fi bottom-of-the-sea stuff presenting seemingly impossible life forms flourishing in the benthic equivalent of boiling poison--or with the brain-bending proposition that all matter on Earth contains traces of a supernova that led to the birth of Sol. No, Low prefers a love story. In the opening sequence, geologist Peter Rona strolls the seashore, reminiscing about his honeymoon 50 years before, when a chance observation kick-started his professional life and the reason he and paleontologist Dolf Seilacher wind up in the abyss.

"Here we were," Rona summarizes, sounding like the maíƒ ®tre d' at a tony Swiss joint, "two old fossils with a chance to solve a puzzle of science."

Narrator Ed Harris joins the dots: the hexagonal-shaped remains Rona discovered that day were "strange burrows of animals that lived hundreds of millions of years before the dinosaurs". Rona and Seilacher, acting on a hunch that somehow convinced Rutger University to pony up a lot of dough (IMAX always prefers sound bites to details), clamber aboard a submersible like the science-mad old goats they are, and we're off..."bound for the harshest place on Earth", three-and-a-half kilometres down on the Galíƒ ¡pagos Rift. Astonishing images of alien life drift by: giant tube worms, engorged with hemoglobin, grip rock spires formed from extruded lava; ghostly shrimp dance through superheated hydrogen sulphide disgorged by hydrothermal chimney vents up to 55 metres in height.

It's all stunning, but the film's larger meaning remains as elusive as those tiny, ancient animals the two pursue but never, ever glimpse.