In the darkness, you can't always trust the light . . . A year has passed since the cataclysmic impact of asteroid AG5. Whilst Earth's survivors struggle against a devastating winter, the world's finest assemble on the International Space Station for a covert mission that could change the course of civilization. Back in the US, Former Director General Steiner is due to stand trial for masterminding heinous acts of terror. As calls for the death penalty gain momentum, those that sit in judgement are unaware that Steiner holds the key to the survival of the entire human race. Meanwhile, marooned in separate locations within the colossal underground realm known as "Sanctuary", Sarah Morgan and Richard Goodwin are fighting for their lives to reach the surface. Unbeknownst to them, their shared purpose is about to awaken a terrifying denizen of the deep . . .