Roberts, Nora: Starlight (Stars of Mithra #1-2)

Hidden Star
She can't remember a thing, not even who she is. But it's clear Bailey James is in big trouble, and she desperately needs private eye Cade Parris to help her find out just what kind. Surely she's not a criminal - but then what on earth is she doing with a bag full of cash and a stunning blue diamond as big as a robin's egg?

Captive Star
Someone had set them both up. Now, handcuffed together, bounty hunter Jack Dakota and bail jumper M. J. O'Leary are on the run from a pair of hired killers. And M.J. isn't talking - not even when Jack finds a gigantic blue diamond hidden in her purse. Everything's telling Jack that the sexy skip he'd been hired to recover can't be trusted - everything, that is, but his heart.