Remember, remember, the 5th of November . . .

It's November in York, and Kitt Hartley is looking forward to a well-earned sabbatical. After years of running a private investigation company alongside her duties as a librarian, Kitt's ready for a break.

But her well-laid plans are rudely interrupted when a bomb explodes in the heart of the city on the eve of the Prime Minister's visit.

Warned that the perpetrators will strike again on Bonfire Night if the politician's visit goes ahead, Kitt gathers her crack team of investigators to hunt down those responsible.

But can they match the mastermind behind this modern-day gunpowder plot, before it's too late?