Catherine, Sophia, Zoe and the other survivors, finally reunited, prepare for the ultimate attack. But it is Bill who is the only one to hold the fate of humanity in his hands, provided he is helped by Isla.
When astronomers detect a transmission from another galaxy, it is definitive proof of intelligent extra-terrestrial life. Earth's population waits for further contact with bated breath, but does not have to wait long. Within days, mankind is all but wiped out, with just pockets of humanity are left in an eerily deserted world. As alien ships appear in the sky, the survivors ask a burning question - who are these attackers and why are they hell-bent on our destruction?