With the future of the planet in grave danger, some far-sighted builders decide that it’s best for humanity to build a subterranean city into which they can retreat. It’s got to be something self-sustaining as they are going to be down there for a couple of centuries. They do provide exit instructions, but over time they get lost and so nobody knows that maybe it’s time to resurface. Now, though, the engineering is starting to give up the ghost and that means power and food are becoming rationed. The mayor (Bill Murray) is hopelessly out of his depth/obsessed with his own position and the chief electrician “Sul” (Martin Landau) is running out of ideas so it falls to the unlikely pairing of youngsters “Lina” (Saoirse Ronan) and “Doon” (Harry Treadaway) to rekindle the population’s appetite to get some fresh air. Luckily, she has a box left to her by her grandmother and as their jobs involve them clambering around the city’s gubbins, they can begin to explore in earnest. This isn’t something they can advertise - the mayor and his thugs will not brook any disenchantment in their city, even if the lights are all about to go out. Now having to fight a rearguard action too, can they discover a way out - and even if they do, is there anything left? I liked the creative style of this film and the fantasy is well explored and unravelled by the engaging partnership of Treadaway and Ronan amidst a city of colourful visual effects. Murray hams up nicely and there’s just the hint of menace from the Dickensianly monikered “Barton Snode” (Toby Jones) to keep the adventure moving along quickly for a ninety minutes of passages, pipe works and grand scale machinery. If you’re looking for complex psychology here then don’t bother, it’s all simply presented family fayre with a cast that look like they are enjoying telling us a story that looks great and vibrates when it’s meant to.