Torchwood: Children of Earth is technically season three of the BBC sci-fi television series. But coming from the perspective of one who watched it "cold" (with no context of having watched the show before), I can say that it is intriguing and gripping enough to be a totally watchable stand-alone five-hour mini-series.
Torchwood is a covert X-Filey group of government operatives... one of those groups that is so deeply hidden (in Cardiff, Wales, no less!) that most of the government (and all of the public) doesn't even know they exist. Why? Well, they deal with aliens. Torchwood consists of Captain Jack Harkness (John Barrowman), a mysterious American soldier with a secret (and very long) past, who has a strange talent for not being able to die (despite getting shot, blown up, or buried just about every episode). His Torchwood partner and love interest (sci-fi gay-boy love?!?! OMG, cool!!) Ianto Jones (Gareth David-Lloyd) is the techie genius of the pack, and Gwen Cooper (Eve Myles) is an ex-cop with savvy street know-how. Basically the three of them make a bad-ass team that have the skills to save the world (woo!).
One day, all the children of Earth stop in their tracks and start chanting, dead-eyed, "We. Are. Coming. We. Are. Coming..." much to the (completely understandable) horror of all adults around them. And just as fast as they zombified, they all suddenly start laughing, chatting and playing again. What. The??? This creepazoid moment happens again. And again. Each time, offering more clues that something bad is going to happen, and that there are some very nasty visitors that are on their way. But who is coming? And why do the messages imply that Ground Zero for this unwelcome visitation is going to be London?
Torchwood is the type of show that mixes lots of action with sci-fi, politics, and morality. But if there is an underlying theme of Children of Earth, it is sacrifice. If it came right down to it, would the average person be able to live by the edict, "All for one, one for all"? There are some very ugly, disturbing moralistic connotations in the storyline that made Torchwood: Children of Earth both gripping and haunting. It took me a few days to shake it off. Now I'll be renting Season One and Season Two to see what I missed in this intriguing sci-fi series.