Vampire Mine

Vampire Mine is the tenth book in the Love at Stake series. The protaganists are Connor Buchanan and Marielle.

Plot
Nothing on earth can make this vampire fall in love. ..

After 499 years of existence, Connor Buchanan has arrived at an inescapable conclusion: he is a cold-hearted SOB. He's been watching his friends—those poor romantic fools—plummet off the cliff into love like a dazed herd of sheep. But not Connor. He knows that love leads to nothing but heartache.

Until Marielle. ..

She is an angel cast down from heaven for disobedience. Trapped in mortal form, she finds a protector in Connor, a Scottish vampire haunted by a dark past. Marielle hopes to heal his broken heart and earn her way back home, but suddenly she has these. . . feelings. This strange yet pleasant physical yearning—for a vampire! Is this the work of a demon luring her into hell, or has this angel found heavenly bliss?