Devil’s Due by Rachel Caine

While Jazz Callender is recuperating from nearly losing her life during their first case for the mysterious Cross Society, Lucia Garza hires a new investigator to their firm: none other than Ben McCarthy. The former Kansas City cop has finally been exonerated of murder, and just in time. Jazz and Lucia have received a new red letter.

But instead of instructions for a high-priority case, this missive contains nothing but a warning: “One of you has made a mistake.” And it’s on letterhead from the Cross Society’s major adversary in a psychic war. With Ben filling them in on his past secretive dealings with the organization, Jazz and Lucia start to believe they may be in bed with the enemy, one that they’ve underestimated at their own peril . . .