London, 1727 - and Tom Hawkins is about to fall from his heaven of card games, brothels and coffee-houses into the hell of a debtors' prison.

The Marshalsea is a savage world of its own, with simple rules: those with family or friends who can lend them a little money may survive in relative comfort. Those with none will starve in squalor and disease. And those who try to escape will suffer a gruesome fate at the hands of the gaol's rutheless governor and his cronies.

The trouble is, Tom Hawkins has never been good at following rules - even simple ones. And the recent grisly murder of a debtor, Captain Roberts, has brought further terror to the gaol. While the Captain's beautiful widow cries for justice, the finger of suspicion points only one way: to the sly, enigmatic figure of Samuel Fleet.

Some call Fleet a devil, a man to avoid at all costs. But Tom Hawkins is sharing his cell. Soon, Tom's choice is clear: get to the truth of the murder - or be the next to die.