Gemma Arterton is in line to star in a biopic about Jeff Buckley.

For the past 200 years, the subterranean metropolis of Ember has survived with the help of its massive generator, but as food stores dwindle and machinery fails, this microcosm of life threatens to slip into eternal darkness.

Joined twins Barry and Tom – the Treadaways – are lifted from obscurity to become a headline-grabbing rock band, and the subject of a documentary film … in a film that is in itself a mock doc.