Crouching Tiger, Forbidden Vampire

Crouching Tiger, Forbidden Vampire is the sixteenth book in the Love at Stake series. The protaganists are Russell and Jia.

Plot
Russell wakes from a coma to find he's become a vampire. Now he has a thirst for revenge. Determined to hunt down the master vampire who turned him, he's used to working alone. . . until he meets Jia. She is after the same vampire for murdering her parents and insists she can help Russell on this mission. Reluctantly, he agrees, and sets up some ground rules:

Rule #1: Their partnership is strictly business. If he holds her a little too close. . . if she looks at him with those exotic eyes. . . well, that has to stop.

Rule #2: He's in charge. Jia isn't used to taking orders and questions every move he makes. So he stops her the only way he knows how.

Rule #3: Don't fall in love. But the kiss that was supposed to quiet her awakens something else in him. . . something forbidden. Because Jia is engaged. To someone else.