Colditz is one of Big Finish’s earlier releases and has a number of claims to fame. It’s the story which introduced Elizabeth Klein to the Whoniverse. It’s the one that’s got David Tennant in it playing a nasty Nazi and it’s the one with the really, really, really bizarre and horrid sound design that makes you wonder how Big Finish even let it past quality control.

The 7th Doctor and Ace arrive at Colditz Castle, are immediately captured and spend the rest of the story trying to escape – but with the added complication of the appearance of Klein, a Nazi agent who has a surprising knowledge of the Doctor and his TARDIS. It transpires that Klein is from the future – a future where the Nazis won the war and she has travelled back in time to capture the Doctor.

The timey-wimey nature of this tale is a little difficult to get your head around to begin with (although get’s clarified greatly in the later releases ‘Klein’s Story’ which was released as part of a trilogy of stories where Klein temporarily becomes the Doctor’s companion) but it is a good conceit for a story which, ultimately, doesn’t have much else going for it.

Putting the time travelling Nazi plot aside for a moment, Colditz is a simple tale about the Doctor and Ace being trapped in Colditz castle and trying to escape. There is a ‘stiff upper lip’ RAF commander; a traitorous English civilian; a nasty, lecherous Nazi and a considerate, compassionate German officer. Ace is bolshy and defiant in the face of the Nazis and the Doctor runs rings around them, or at least before he gets dragged off into the time travel plot. It feels a little like the TARDIS has materialised in a black and white war film rather than the real history.

Fortunately, the mystery of Klein lifts the story beyond it’s rather mundane trappings and gives the listener something more original to enjoy. That said, the ‘Nazis win the war’ trope isn’t exactly original itself but I do want to find positives in this story. The guest cast is also excellent. Nicholas Young (from The Tomorrow People’ is excellent as Flying Officer Gower and David Tennant and Toby Longworth contrast each other well as the bad cop and good cop Nazis. Tracy Childs is superb as Klein and it’s easy to see why she eventually returned in a more regular role. McCoy and Aldred are both on top form and overall the cast make a really good job of what, to be honest, isn’t the most original of scripts.

But why am I so desperate to find the good in this release? It’s because it is a really difficult story to listen to – physically. The sound design on this is utterly atrocious. Interior scenes sound like they’ve been recorded in a metal box. Characters walk, accompanied by a clip clop sound effect. Background ‘wild tracks’ of prisoners chatting literally cut off dead when a main character starts talking. It is really, really bad and when there are audio stories which predate even Big Finish’s early releases that have better, more accomplished sound design it is surprising this was allowed out of Big Finish Towers. I’m also surprised more online reviews make barely a mention of it because, to my ears, it almost made the whole thing unlistenable.

It’s also the beginning of the rather odd narrative decision that BF took to have Ace start referring to herself as McShane in an attempt, I assume, to ‘mature’ the character. It doesn’t work and, I’m assuming BF realised this, as it doesn’t last past many 7/Ace releases. The maturing of Ace is achieved far more effectively with the introduction of Hex.

I do like Colditz. It contains a number of the tropes which have become common the World War Two stories and it isn’t the most original of stories but the cast make the best of it and Klein and her story are intriguing. The sound design is appalling but if you can ‘hear’ past it, it’s an enjoyable four episodes.