The London rookeries are slums, rife with criminals, and shunned by the upper crust.

But someone there intends to murder one of England's greatest leaders, and Marcus Kane, Lord Chadwick, will follow every clue, even into the bowels of London's underground. But he can't find his way alone.

A partner is required.

Fantine (Fanny) Delarive is perfect. She knows the slums better than any, has survived its labyrinth alone for years, and knows every criminal lurking in every dark corner.

Then, the investigation detours the pair into the bright ballrooms of the ton.

And Fantine fits in here, too.

Which changes everything.

Lord Chadwick knows a woman of Fantine's ilk is entirely unsuitable for him. But she's infinitely more exciting than any well-born lady he's ever met.

Now much more than an acquaintance with the independent, self-reliant Fantine is required... and it must end with nothing less than marriage.