S04E09: 'Forest Of The Dead'

Talk about raising the bar. The brilliant 'Forest Of The Dead' taps into deep-rooted psychological fears lurking in the shadows of one's mind, brilliantly building upon the intricacies and visceral thrills established in the opening part.

Donna's journey in this episode takes the essence of that old sci-fi concept - the parallel world - and gives it a stunning twist. Donna has all her dreams come true, finding an ideal man who can't answer back, two lovely children and a strong sense of belonging. The fact that it's all fake allows Catherine Tate to deliver her strongest performance to date, as the rug is ripped from beneath her feet in harrowing style.

Quite a few Doctor Who stories have been wrapped up fairly unconvincingly, with some overly convenient plot contrivance rearing its head in the final few minutes. Not so here. The little girl's emergence as a computer hard drive and River Song's self-sacrifice and resurrection are all cleverly structured and realised, providing a satisfying conclusion to the complex plot.

Then, just when we breath a hearty sigh of relief as normality is restored, Donna's dream man cannot muster the voice to shout after his beloved one because of his stutter. That moment, as Lee is teleported away, is cruel, clever and utterly heartbreaking - as is the look on The Doctor's face as he stares, handcuffed, at River Song's corpse.

The sight is an emotional burden that he will have to carry all throughout his future relationship with the archaeologist, a twist that further shows just how clever writer Steven Moffat is at manipulating timelines to make compulsive drama. David Tennant and Alex Kingston have such a believable chemistry together that one hopes they'll be reunited at some stage in the future. Perhaps then we'll learn exactly why he told her his name.

Over the course of this two-parter, Steven Moffat has tapped into our physical fear of the darkness and our psychological fears about losing what's precious to us. Chuck in great performances all round, well-paced direction from Euros Lyn and a Murray Gold score that often evokes the scare-maximising sounds from Lost - and you have the most complete episode of Doctor Who for a long time.

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