Torchwood (2006 TV Series) - Season 3 - Episode 5

Season 3, Children of Earth (5 episodes, BBC One, 2009), is a single, tightly plotted thriller. Decades after a secret deal with alien “456” ambassadors, the UK government is blackmailed to hand over 10% of the world’s children. As children worldwide fall into trances and speak in unison, Jack is hunted, Ianto is killed, and Gwen now pregnant helps expose the conspiracy. In a grim resolution, Jack sacrifices his own grandson to save the rest, then departs Earth, leaving Torchwood effectively disbanded.