The narrative is very well plotted and paced, allowing several strands a good amount of exposure before merging together for the exciting cliffhanger. The reintroductions of UNIT, Martha, Donna's family and the war-loving Sontarans are all seamlessly interwoven into Helen Raynor's script - a marked improvement on the mess that was 'Daleks in Manhattan'. In particular, the interaction between Donna and Martha is charmingly written, confounding the expectations of those who foresaw a full-on cat fight.
In addition, the central plot that binds these disparate elements together - the Sontaran plan to gas the Earth via carbon-free Sat Nav - is consistently gripping, intriguing and benefits from the momentum generated by the pre-credits sequence. Furthermore, Christopher Ryan is superbly cast as General Staal and uses his trademark 'constipated' voice and grumpy eyes to great effect. In contrast, Commander Skorr's voice is distinctly lacklustre.
'The Sontaran Stratagem' does have one noticeable flaw in the shape of Douglas Mackinnon's inconsistent direction. The first unveiling of an armour-clad Sontaran in the cloning chamber is depicted via a highly underwhelming long shot. Surely the iconic monsters deserve a more tension-filled unveiling to a new generation? The grand reveal of the Martha clone is similarly botched due to shot selection worse than English batsmen during the last Ashes series.
Fortunately, inspired moments like The Doctor's use of squash to incapacitate General Staal and Donna's alien flashbacks (cleverly juxtaposed with her mundane domestic life) mean that our interest is sustained throughout. Some say that the proof of the pudding is in the eating, and similarly the proof of a first part's effectiveness lies in how much we want to tune into the conclusion. Bring on 'The Poison Sky'!
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