In the cities and untamed wilds of Ireland, monsters are rising up against Unionists. Luckily. Sam and Hel aren't English.

Samantha Harker and Dr. Helena Moriarty might have solved the Paris case, but that doesn't mean the Royal Society for the Study of Abnormal Phenomena trusts them. Sam's power to see into the minds of monsters is a slippery slope to corruption. Worse, Hel's uncanny habit of turning up wherever her notorious father's hand is felt has the Society questioning whether he exists at all . . . or whether it's been Hel all along.

So when Special Branch requests aid in Ireland, the heart of Professor Moriarty's hidden empire, they send another agent to monitor them: Van Helsing, who is perpetually suspicious of Sam and a bit of an arse.

Their investigation takes them from ancient ruins to the clandestine clubs of the rich and powerful, untangling the mysteries of magic, monsters, and men. But even as Sam and Hel fall deeper into each other's orbit, the secrets between them multiply. Things Hel can't bear to confess; things Sam doesn't dare confide. Things which not only put Sam in terrible danger from Van Helsing, but leave her haunted by death omens, mysterious black feathers, and a song no one else can seem to hear. And, as ever, Professor Moriarty lurks in the shadows, waiting to make his next move . . .