This review contains spoilers.

Sometimes The Doctor must look at this planet and turn away in shame.

"Torchwood" may be its own show for a mature audience, but time and time again it has shown how easily it can integrate with the mother series for a bigger scale of adventure -- like Daleks, the end of the world and entire planets stolen from time itself - which only raises the question of if the situation is so dire, why wouldn't The Doctor materialize in his little blue box and save the day?

Before any such questions can be muttered, Gwen (Eve Myles) so eloquently offers an answer so desperate and devoid of all hope - almost desolate -- that it perfectly captures the tone of the tone of the miniseries as it squashes a simple niggling question. The Doctor is ashamed.

What more needs to be said? The Doctor, a man that can see the whole of time and who looks at humans with inspiration, love and admiration, turns away in shame of the enduring darkness that is the Human soul. From there on in, "Day Five" gets darker, heavier and offers the most shocking and inhumane of twists that it can easily be considered among the finest hours of British television.

Forget the mind-bending reveal of why the 456 actually want the children of Humanity (not for any noble purpose, simple for "the hit") or that the worlds leadership is actually willing to make such an exchange, the real tragedy comes in the form of two families ripped apart through the crisis.

The first is the family of John Frobisher (Peter Capaldi) who are offered to the 456 as a PR stunt. Thus far in the miniseries, Frobisher has been made accessibly and even likable given the decisions he has made : even more so through Susan Brown's wonderfully performed speech in the holding cells. And so when it comes down to Requisition 31 - an ominous request to say the least - his course of action becomes immediately clear and it is hard not to feel a pang of regret for the situation he finds himself in.

"I think people will forget just how very good he was," she tells Lois (Cush Jumbo) in an emotional exchange. Both Capadli and Brown have been completely under sung throughout this miniseries and from the beginning have brought a sense of class and sophistication to the science fiction adventure.

And just when you think you can't take any more, Jack (John Barrowman) delivers a final blow of brutal cold calculation that he is virtually unrecognizable as the Jack we know. Remaining incredibly conclusive, "Day Five" delivers a victory that tastes as bitter as defeat, leaving you completely satisfied and yet somehow curiously hollow.

What Worked

As Col. Oduya (Charles Abomeli) steps into the top floor of the MI5 building for an audience with the 456, Ben Foster's score is almost a lullaby. It's simple, innocent and almost comforting. Easing viewers into the room is the first step in creating an atmosphere of shock and revulsions as the 456 announce they need children for "the hit." The synthetic voice of the alien remains lifeless yet somehow carries a degree of menace and

In much the same way, John Frobisher's final moments have a similar effect but the vocals are far more penetrating and far more haunting.

The drive to Ianto's family is an emotionally vulnerable moment for Gwen and gives an unusually untainted look at Gwen as a character. It is the kind of moment that typical episodes simply don't have the time to deal with and are either limited to a handful of minutes or removed entirely. And what makes this scene so compelling is the unadulterated emotion that eventually leads up to Gwen receiving a verbal slap from Ianto's sister.

What Didn't Work

Although it may make the miniseries so much more potent, there is a deep burning desire to see Jack's grandson, Steven, gasp a breath of new life following Jack's plan to rid the world of the 456 : a desire that goes unanswered.

Meanwhile, the irrelevance of Col. Oduya, the sole UNIT presence on the show, continues to spiral unchecked.

Giving Credit Where Credit Is Due

"Torchwood: Children Of Earth" stars John Barrowman, Eve Myles and Gareth David-Lloyd. "Day One" was written by Russell T. Davies and was directed by Euros Lyn.

Torchwood: Children Of Earth airs this week on BBC One, and then launches on July 20 on BBC America.