Unknown Soldier

A computer engineer from the defence industry is found dead in his garage. The official word is suicide, and that's where a sensible man leaves it. Clark is hired to look anyway, and what he finds suggests the suicide was a silencing. Deakin tells him to steer clear. Clark doesn't, and the episode's engine is that disobedience.

J. C. Wilsher and Julian Jones wrote it, Ross Devenish directed, and the case is one of those that could prove deadly for everyone involved. Defence industry secrets are volatile by definition. But the deeper Clark goes, the more the investigation takes on a quality of menace. The guest cast carries a name that jumps out now: James Nesbitt, years before Cold Feet and The Hobbit, plays Sean Phelan, and Lolita Chakrabarti's Zahida Khan, who would later write the acclaimed Red Velvet, and Rashid Karapiet's Abdul Khan round out a world where nobody can be sure who's listening. Eve Bland's Ellie Hughes rounds out the cast, and Sylvestra Le Touzel's Sarah Teale and Barbara Wilshere's Kate Roberts are there too, keeping the season's regular world within reach.

The tension the episode runs on is the old familiar one, sharpened by the new setting. Deakin's caution is professional and probably right; Clark's curiosity is professional and definitely dangerous. Watching the two of them pull in opposite directions is the pleasure of the hour.

It's a warning episode in the best sense. The truth may be just beyond reach, and the show leaves you with the sense that some secrets are expensive to even look at. Clark keeps looking, because that's who he is, and the episode doesn't pretend that's a safe way to live. The garage where the engineer died is the episode's still centre, revisited at the start and again near the end, and the second visit reads differently. Deakin's warning is the most honest thing anyone says in the hour, which is its own kind of statement about the world the show lives in.