The Seventh Doctor is reunited with an old friend… but others aren’t so keen to see him.

Elizabeth Klein’s creator, Steve Lyons, returns to pen this final story in the trilogy of “New UNIT” tales that have appeared periodically this year, charting the 5th, 6th and now 7th Doctor’s encounters with an unfamiliar version of what once was a mainstay of his life. It’s fair to say that this UNIT is far removed from that which he remembers, with another new commanding officer, Richard Gibson’s Colonel McKenna, who hasn’t had shared experiences with the Doctor, and is far more interested in working with (or rather, ordering around) Klein, currently the UNIT Scientific Adviser. As Lyons notes, this is a very different version of Klein from the one first seen in Colditz (both the 2001 play and the castle itself!), but his knowledge of what makes her – and indeed this incarnation of the Doctor – tick is crucial as the story hits its third act, aided by nicely judged playing by both Tracey Childs and Sylvester McCoy.

The story also marks the return of Blake Harrison’s Daniel Hopkins, a character who is now living with the consequences of his actions in the previous story. Harrison delivers a strong performance as the broken man who’s found something new to pursue – there are a couple of long monologues that could easily have pushed the character into caricature but which Harrison handles well.

Jamie Anderson’s direction is assured with Simon Power’s sound design and music helping set the Spooks-like atmosphere of double dealing and betrayal that is at the heart of the story.

Verdict: A different sort of trilogy comes to a satisfying conclusion. 8/10

Paul Simpson