The search for a missing Sontaran officer leads to an unlikely alliance for Kate and Colonel Shindi.

Andrew Smith is fast becoming Big Finish’s “go to” writer for the Sontarans (if he hasn’t done so already) and he produces another highly enjoyable encounter with the clone species for this box set. Various threads are set up at the top of the story – Osgood’s hijacking by one of her former colleagues; Shindi’s investigations in the Ardennes – that come together quite a bit later in proceedings than you might expect. This gives Ingrid Oliver a chance to show Osgood’s mettle when she realises how deeply in trouble she has become, and Jemma Redgrave and Ramon Tikaram opportunity to show how the military commander and the scientist work very well together.

Dan Starkey has multiple different Sontarans to portray, and amply demonstrates how members of a clone species can be told apart – at no time during this are you confused as to which of the Sontarans he’s playing, all through slight differences in tone and texture of voice. Beth Goddard and James Wilby are the villains of the piece, but never allow their performances to spill over into melodrama.

The contrast between human and Sontaran views of military operations also is key to the way in which the final act plays out, and there’s even a brief shout out to earlier UNIT encounters.

Verdict: A terrific piece of Doctor Who. 10/10

Paul Simpson