'Your ridiculous Art. It's as twisty as you are, and that's saying something.'
It's twenty years into the reign of Queen Victoria. The Agency for the Benefit of Registered Artisans has been established to help and protect magic-users and regulate their Artworks. The use of illicit Art is heavily punished. The coldly self-possessed Kit Whitely is an Artisan whose specialty is opening doors and locks. That makes him very popular with a certain type of criminal, so he's hiding out in a remote Somerset village hoping for uninteresting times. He's starting to feel safe for the first time in his life.
Cheerful bounty hunter Alexander Locke has other ideas. He's obliviously barging into Kit's peaceful new life to arrest him for the use of illicit Art and drag him back to London. But he's a man of divided loyalties and so he's also intending to use Kit for illicit purposes of his own.
How much trouble could one pissant little thief give him, really?