It is PG, after all.
City of Ember – I must remember a PG movie is usually best-suited for children, and City of Ember is a proper candidate. Except for a grubby, oversized mole that eats people, nothing other than careering amusement-park-like rides generate enough scares to get a censor's or censorious mother's attention.
For a couple of hundred years, the City of Ember has survived deep in the earth as the result of builder-elders deciding to spare future generations the pain of living above ground, presumably because of the mayhem we have caused. At the end of the two centuries, a little box left by the elders will hold the much-needed map as the infrastructure is exhausted (annoyingly the lights regularly go out to show the horror). Two teenagers decide to find the way out, much to the chagrin of the Mayor (Bill Murray) and with the help of one dad (Tim Robbins), who has tried and failed before to leave.
It's all formulaic stuff about the kids' miraculous decoding of the instructions and the Journey-to-the-Center of the Earth feel, along with a Charles Dickens dirty world of old machine parts and unwashed humans. The allegorical possibilities are there, of course, about the death of the planet, work as labor not love, and the spirit of youth to overcome years of adult lassitude.
If you have to take the children, then look forward to seeing Bill Murray scream in fright and Martin Landau overact as an old man. Come to think of it, he is an old man, and this is an old story.