Conduit

Think all blood is the same? Think again.... Copper has always been in her twin sister's shadow. But now her sister's been kidnapped, and only Copper can save her. Trouble is, she'll need help--from a domineering vampire who knows just how special Copper truly is. Bastian knows Copper is a rare woman, and not just because of the mind-bending passion she makes him feel. Copper is a Conduit--a rare human whose blood can magnify a vampire's powers. Now he has to protect her, claim her for his own...and somehow keep his vampire brethren from discovering her secret. Copper has what she's always wanted, to be unique and special. But being the Conduit isn't a bed of roses. She could be used by Bastian's vampire enemies for all eternity--or killed to prevent it. And how can Bastian himself resist the urge to taste blood so rare?