The fantastic groundwork set up by the previous episode's intricate plotting isn't fully capitalised upon in this week's decidedly average conclusion.
Again, Douglas Mackinnon's direction lapses into occasional ineptitude and scuppers several key moments that were probably brimming full of spark and tension in the script. This is most evident in the battle scenes between the Sontarans and UNIT, which are devoid of both energy and clarity. The death of the amiable soldier Ross is also poorly handled on a visual level, with David Tennant's subsequent emoting doing its best to address the tragedy of the situation. It's also thanks to Freema Agyeman's performance that the death of the Martha clone is surprisingly touching.
The moral core of the revived Doctor Who is fittingly present throughout the episode in The Doctor's overt anti-gun stance. However, this seemingly simple theme is fascinatingly subverted by The Doctor's threat to become a suicide bomber on board the Sontaran ship and die for a good cause. Given the fire and sorrow conjured up by Tennant's eyes, it appeared to be more than just a bluff. This adds a new layer of complexity to the show that will hopefully be explored in future episodes, especially given The Doctor's past as a soldier in the Time War.
The narrative does occasionally lapse into easy 'get-out' clauses, like the use of Luke Rattigan's atmospheric converter to clear the skies or Sylvia simply smashing the car window to save Wilf - an axe-wielding moment that makes us wonder why The Doctor was simply strolling around the street while poor Wilf was spluttering away. Nonetheless, the ultimate resolution to the plot is very satisfying, as the fiendish Rattigan has his moment of redemption by blowing the enemy spaceship to smithereens. It's a classic Doctor Who trope, with particular echoes of Galloway's explosive demise in the 1974 story 'Death to the Daleks'.
Away from the serious wartime nature of the story are a handful of hilarious moments to raise a few giggles from behind the sofa. The Doctor's "are you my mummy?" moment is self-referential genius, Donna's Alan Partridgesque "back of the neck" one-liner to a freshly 'vented' Sontaran works well, and the Tardis key exchange between the two time travellers is refreshingly devoid of any sentimentality and played for laughs.
Overall, writer Helen Raynor and the ensemble cast deliver the goods in 'The Poison Sky', but one can't help but wonder just how good it could have been if Graeme Harper was calling the shots from behind the camera. It’s rather apt that the episode, like a Sontaran, falls short.
