Where Demons Dare by Kim Harrison

The sixth book in Harrison's New York Times bestselling urban fantasy series starring Rachel Morgan. A pacey and addictive novel of sexy bounty-hunting witches, cunning demons and menacing vampires. To save the lives of her friends, Rachel did the unthinkable: she willingly trafficked in forbidden demon magic. And now her sins are coming home to haunt her. As Rachel searches for the truth behind a terrifying murder, an even greater menace threatens, for the demon Algaliarept will stop at nothing to claim her, and the discovery of a shocking family secret throws Rachel's entire life into question. If she is ever to live free, Rachel must walk willingly into the demonic ever-after in search of long-lost ancient knowledge. But when you dance with demons, you lay your soul on the line... and there are some lines that should never be crossed. Published as 'The Outlaw Demon Wails' in the US.