It is austerity-ridden, black-market-riddled, post-war England and MI5 has pushed Cockney cat burglar and jewel thief Jethro out onto the rooftops of London again in defence of The Realm. And if that was not bad enough, London's top villains want him to do a bit of burglary for them too. Ever looming in the background are the twin spectres of the growing communist menace and a resurgence of fascism. There are even rumours that an American OSS agent is roaming around London with his eagle eye set on someone who looks an awful lot like Jethro. Things turn decidedly deadly when Jethro stumbles across a Royal cover-up and an extreme right-wing plot to topple Britain's new Labour Government. And all this is a mere precursor to Jethro having to pull off a very dodgy and dangerous caper, the success or failure of which could save England from going to the dogs or spell curtains for Jethro.

Cockney cat burglar and jewel thief Jethro is as smart as he is streetwise, but even he has to be a bit nimble to prosper in the austerity-ridden, black-market-riddled world of post-war England. Having barely survived the war, Jethro tells everyone he's gone straight and takes up as a stagehand around London's many theatres. But the truth is that hiding in plain sight around London's West End is the perfect cover for his diamond capers in wealthy Mayfair and Belgravia. Jethro steals into the embassy of an Iron Curtain power to pinch some fabled Czarist jewellery, but his daring caper brings him to the attention of His Majesty's Secret Service and they blackmail him into going back to retrieve a secret code-book and help a beautiful cipher clerk defect. It's all a set-up for a thief to catch a thief that pits Jethro against London's top villains, as well as one of the Soviet's topmost secret agents and assassins.