Heath Kavanaugh lost years of his life working for a covert agency that ended up being the enemy. Knowing they put something inside his head--constant, incomprehensible whispers--is driving him crazy.

He needs answers, but they're nowhere to be found.

What he definitely doesn't need is to fall hard for his Linear teammate's younger sister, Jacquelyn--the adorable linguistics doctoral student who happens to be in the wrong place at the wrong time.

Especially when Heath's attention puts her directly in the path of a danger he thought was gone for good. To stop it, they'll have to figure out what's in his head. And hope it doesn't destroy them all.