Envision the preserves in your grandparents’ cannery as a city, and that’s Ember – something that’s improbably, and a bit disgustingly, lasted longer than intended.

More than 200 years after “the world ended” on vague, but likely nuclear, terms, this underground city is past its flee-from date. Its infrastructure is crumbling. Electric blackouts roll like it was California. The Great Day of Singing is an opiate for the masses. And face-stuffing Mayor Cole (Bill Murray) seems without a care.

Those are refreshingly heady concepts for a children’s film, and City of Ember feels like an election-year story geared toward those unable to vote until 2016. It’s also a sumptuous visual primer for its filmic fantasy forefathers — Terry Gilliam, Jean-Pierre Jeunet, Alex Proyas, the Wachowski Brothers, George Miller, Peter Weir and Tim Burton — and a narrative cousin to the ideas of Roald Dahl and George Orwell.

If only this story of discovery didn’t feel so deliberate. The wow factor of Ruth Myers’ costume design and the practical-effect sets wears off. And unlike Monster House, director Gil Kenan’s animated summer surprise from 2006, the action doesn’t kick in until the film’s finish.

Worse yet, Murray is Steve Zissou when the movie needs him to be Peter Venkman. Somehow, this mayor has sweet-talked the people of Ember into eating from his hand, but it’s something the movie never shows.

A lack of whimsy and wonder in Ember is even more surprising given its script comes from Caroline Thompson. With Edward Scissorhands, The Nightmare Before Christmas and Tim Burton’s Corpse Bride, Thompson handily crafted many fantastical films for Burton.

At least she’s got great names to work with from Jeanne DuPrau’s novel — monikers like Barton Snode, Lizzie Bisco, Arbin Swinn and Sadge Merrall.

The main characters have good ones, too — Doon Harrow (Harry Treadaway, a combination of C. Thomas Howell and Freddie Highmore) and Lina Mayfleet (Saoirse Ronan, Oscar-nominated for Atonement). Together, they must do what their elders couldn’t — find a way out of Ember that avoids death from drowning.

A box locked for 200 years and meant for Ember’s mayors was lost to time and the cluttered closet of Lina’s demented grandma (Liz Smith). When Lina finds it, she opens it to find instructions for exiting Ember — only to have sister Poppy (Amy and Catherine Quinn) use them for teething.

When it becomes clear Mayor Cole and his henchman Snode (Toby Jones) are up to no good, Lina and Doon scramble to piece the instructions together. Helping them are: Doon’s father, Loris (Tim Robbins); lifelong pipe worker Sul (Martin Landau in a gem of a role); and gardener Clary (Marianne Jean-Baptiste).

With cobblestone streets, lines for trams long ago put out to pasture and subterranean tunnels galore, Ember resembles a rusted-out foundry … and a socially frightening place to live.

For the kids who will pick up on it, it’s a cautionary screed against a lack of innovation, invention and improvement. It could be one heck of a wake-up call if it bothered to sound its alarm earlier and louder There are some magical moments in Ember’s resolution — most involving a gigantic waterworks — charged with the rush of getting at the guts of machinery (in this case, the city).

While not quite the puzzle-box mystery it should be, Ember is a social studies lesson by way of John Christopher’s The White Mountains aesthetic. And, like The Spiderwick Chronicles, it understands kids can handle a little chaos in their entertainment.