Blood Knight Chronicles Series by Linda Thomas-Sundstrom

Can his dark legacy protect her... Madison Chase, an American newscaster, is in London to follow a missing girls case. But research leads Madison to the discovery of an enclave of ancient vampires that run the London underground, which puts her in danger. Christopher St. John has lived for centuries, and can't escape the dark legacy that created him. That legacy also makes him a rogue vampire's worst enemy... moreCan his dark legacy protect her... Madison Chase, an American newscaster, is in London to follow a missing girls case. But research leads Madison to the discovery of an enclave of ancient vampires that run the London underground, which puts her in danger. Christopher St. John has lived for centuries, and can't escape the dark legacy that created him. That legacy also makes him a rogue vampire's worst enemy. His desire for the redhead who digs into the past is forbidden by the oaths he has taken... and as Madison's investigation continues, she must discover if St. John is a trusted Protector--or if she's being seduced by a monster. This best-seller is a good fit for fans of Lynsay Sands. less