Fans of the popular young adult series of books by Jeanne DuPrau will be right at home and mostly delighted to find themselves in the world that director Gil Kenan has tunneled out for them in "City of Ember," from the sputtering flood lamps high above the city to the clanking pipe works where the world is steel and iron and dripping water.

The seemingly doomed Ember was built to last 200 years, and it's year 241. It's run by a mayor (Bill Murray, in a wonderful turn) who is corrupt and not very bright.

Doon Harrow (Harry Treadaway), the only son of an eccentric inventor (Tim Robbins), and Lina Mayfleet (Saoirse Ronan), want to save the city. Lina discovers a mysterious box left behind by the Builders, the almost mythical ancestors who exist now only in portraits. The box has a map and "Instructions for Egress," which starts to sound like a great idea when they discover what's hidden in Room 351, but it becomes clear the mayor doesn't really want anyone to egress anywhere.

Kenan imagines a world that looks like an old movie set of an English village, a place deliberately artificial. (Perhaps too false. It kept reminding me somehow of Whoville, minus the pastels.) But behind the city walls are the real guts -- and secrets -- of the city, the muck and dirt and grease and foul odors of dank places, and this is smartly where Kenan keeps most of the story.

Doon and Lina will have to save themselves to save their city. There are adults they can trust, and those they can't, and scary things in the dark that aren't just shadows. They are after something they can't even name: sunlight.

It's not an entirely convincing trip, but it is the sort of satisfying movie you wished they would make more often.

-- Neely Tucker (Oct. 10, 2008)

Contains mild peril.