Immortal obsession - Linda Thomas-Sundstrom

Bound to oblige her every desire.
When a rogue group of human-hating vampires overtake London, the elite immortals who own the city turn to American newscaster Madison Chase. If she can convince someone to help her infiltrate the dangerous faction, she just might stem the bloodshed and find her brother in time.

The instincts that keep St. John from being fully human make him the rogues' worst enemy. His all-consuming desire for Madison is forbidden. But, as the investigation escalates, Madison must discover if St. John is her trusted Protector - or if she's being seduced by a monster!