Claustrophobic horror from French director Franck Vestiel. A man, Tolbiac (Clovis Cornillac), wakes to find himself at the bottom of a dark, mud-filled cave, deep underground. Naked, and with no recollection of how he came to be there, or why there is a dead man lying beside him, he struggles to his feet and moves towards the only light-source visible. Appearing to be in a labyrinthine network of tunnels, he soon discovers what seem to be abandoned laboratories, containing evidence that he's not alone. As he struggles to find a way out of his underground nightmare back to the surface, he soon realises he has become the quarry of some particularly ravenous predators.