CIA "Stake-Out" agent Emma Watson takes her job personally, having lost her parents to vampires six years earlier. Ambushing vamps in New York City's Central Park, Emma neither suspects nor particularly cares that there are, in fact, two vampire factions: one evil, bent on destroying humanity, and the other good, having eschewed people blood for a synthetic substitute. One of the good guys, Scottish vamp Angus McKay, has been assigned to stop her nightly patrols, but instead finds himself falling in love. Soon Emma's deep-rooted beliefs are coming unmoored: undeniably attracted to Angus, she can't bear the thought of loving-or even trusting-a vampire, but she's left without a choice when Angus's ex-lover decides to capture them both as a gift to her evil overlord.