Sapphire Diamond is on top of the world. She's the star of a killer collection and has just been promoted to head designer of Red Silk. However, her life is about to be turned upside down by bat shifter traffickers.

Cassia Sol is part macho protector but all vampire bat shifter. The second she catches the scent of her mate, her bat wants to claim Sapphire, but Cassia is unwilling to make that big a leap from strangers to lovers.

As passion turns to affection, Cassia's mate claims her. That bond ensures the brown bat traffickers will have to fight the Midnight Agency, not just Cassia, to get to Sapphire. Blood ties run soul deep and sisterhood is forever.