Kristy's Puzzle

A passion for cryptograms shouldn't lead to kidnapping...
Kristy Collins' visit to her best friend becomes a fight for her freedom, and maybe even her life, after she partially solves an encrypted magic spell. She needs help to stay out of the hands of power-hungry men, but unfortunately, her protector is the man whose heart she broke eighteen months ago.
Mark Simmons would rather search for terrorists in a jungle than be stuck alone with his ex-girlfriend. But after she's almost kidnapped, he reluctantly agrees to play her bodyguard. Now, he must work with Kristy to find and stop the men who want her to decrypt a spell that could give them control of anyone in their way.
Mark tries to keep his distance from Kristy, but he sees she's changed. It might be more difficult than he anticipated to preserve the walls around his heart as he protects her.
This book can be read alone, but some characters are introduced in the preceding books. This is an 18+ story.