Old wounds are reopened when Lynley investigates the disturbing death of his godson, more than a decade after the boy's disappearance.
Poirot is issued with a deadly personal challenge when a series of letters, mysteriously signed ABC, lead him to a string of brutal murders where Poirot could be the next victim.
When all the children in the world suddenly stop in their tracks and in unison chant the phrase 'We are coming', the Torchwood team know they have an alien force to reckon with, but how is the government involved?
Jack explains to the rest of the Torchwood team what happened in 1965, and why the children had to be handed over. Meanwhile, the 456 announce that if their demands aren't met, they will wipe out the human race.
Torchwood are forced into hiding underground to avoid the government squad's action against them and their families. Meanwhile, the government makes plans for the mysterious Floor 13.
