The Givenchy Code: Code (Book 1)

As if a recent breakup, scrounging for rent money, and lusting after designer shoes weren't enough to make graduate student Melanie Prescott's life challenging, suddenly she's practically living The Da Vinci Code. A mysterious stranger is sending obscure codes and clues her way and she soon discovers she has to solve them in order to stay alive. With stakes like that, her dissertation on "the derivation and primary characteristics of codes and ciphers used by prevailing nations during wartime" is looking a little less important than it was yesterday. Right now she's just worrying about living to see tomorrow. The only bright spot in the whole freakish nightmare is Matthew Stryker, the six-foot tall, dark, and handsome stranger who's determined to protect her.