In 1965 twelve children are gathered together on a deserted moor when they become surrounded by a harsh, bright light, and then suddenly they are gone. Back in the present day, all over planet Earth, children stop moving. Stop playing. Stop laughing. Stop everything. Then, as one, they begin to speak with the same voice, announcing to the governments of the world the imminent arrival of a new alien threat. It becomes clear to the Torchwood team that this isn't the aliens' first visit to Earth, and a terrible price is going to be paid for sins of the past.
At 8.45am, every child in the world suddenly stops, chanting the words "we are coming" again and again. Whilst investigating, the remaining Torchwood team face greater personal and professional challenges than ever before, having to work with their numbers depleted.
Torchwood are forced underground, as the government takes swift and brutal action. With members of the team being hunted down, only Lois holds the key to Torchwood's salvation - but she is helpless as her superiors make plans for the mysterious Floor 13.
The eyes of the world turn to Britain, as the 456 announce, 'We are here'. As a pillar of fire descends upon London, the members of Torchwood must battle to protect their own families, as the fight gets personal. But will Clem's memories destroy everything?
Torchwood finally learns the truth about the events of 1965. But Britain is in danger of becoming a rogue state, and everything now pivots around John Frobisher, as the Ambassador of the 456 destroys its old allegiances and reveals its true intent.
Torchwood is defenceless, and Gwen Cooper stands alone, as the final sanction begins. As violence erupts and the world descends into anarchy, an ordinary council estate becomes a battleground where the future of the human race will be decided.