Backtrack

A routine house break-in turns fatal for Sammy Layden. The cat burglar gets in, finds more than he bargained for, and ends up dead, which is a steep price for a night's work. What he stumbled across was a drugs smuggling operation with connections to the Arab Embassy, and whatever he saw was worth killing for. The trouble spreads beyond him too: once CI5 realise the scale of the operation, it is clear the burglar's death was never going to be the end of it.

That is where CI5 come in. Bodie and Doyle take the obvious route, which is also the strange one: they become burglars themselves and work backwards through Sammy's movements, trying to work out what he found that was so deadly. It is the sort of patient, footsore investigation the show does well, retracing a dead man's route and feeling the danger close in with every step. Along the way Doyle has to cope with the attentions of Marge Harper, which gives the hour a lighter thread running underneath the grim stuff.

Brian Clemens and Don Houghton wrote it, Christopher King directed. Liz Fraser, a familiar face from the Carry On films, plays Margery, with Michael Elphick as Garbett, John Bennett as Truitt, Brian Gwaspari as Pulman and Brian McDermott as Miller. Stacy Davies is Sammy, and Michael Halphie is Gunman 1.

The neat trick is the backtracking itself. Watching two professionals walk a dead man's footsteps is a satisfying way to build a mystery, because the story arrives in the order it happened rather than the order it was discovered. And Michael Elphick is always worth the price of admission, even in a small part; he brings a worn, dangerous quality to Garbett that the script only hints at. The embassy connection keeps the stakes higher than a simple burglary case, which gives the pair a reason to keep going when the trail goes cold.

It is a solid, workmanlike episode with a better than usual idea at its centre, and the sight of Bodie and Doyle as a pair of clumsy cat burglars is worth the hour on its own.