The third and fourth installments of Torchwood Children of Earth establishes why the 456 have chosen Britain and what they want. It also implicates Jack in the heinous decision to give children to the 456 in 1965 in exchange for a vaccine to a virus the 456 say is going to devastate the human population. No one involved asked what the 456 were going to do with the children but only that they were going to continue to live. (The reason the 456 take them is the most anti-climactic moment of the entire series’/season’s plot.)
The bulk of Episode 3 is taken up with the regrouping of the Torchwood team in the forgotten London Office, where Ianto initially worked. They use “criminal techniques” to rebuild their computer, cellphone, and transportation needs and make a makeshift command center. They also rescue the only surviving orphan of the 456, who is horrified to discover the only man who can save him is also the man who has been haunting his dreams for the last 40+ years. His revelation about what happened to him and his friends, coupled with Jack’s assertion that sacrificing a handful of orphan children was worth the lives of those presumed saved, shifts the way the team sees him in E4; it is only momentarily, but does serve to undermine the triumphant return of Captain Jack Harkness (E3) that is a key component of this mostly boring episode.
As predicted, Louis also becomes a key player. Gwen convinces her to wear video cam contacts that record both the alien arrival and the initial contact. They will later hope to use this footage to stop the child sacrifice.
Other things in this episode: The government holds Jack’s daughter and grandson hostage after she puts up a valiant fight. This may seem minor, but will prove to be a pivotal plot twist on the final episode.