Conscience vs. Conviction...both come from passion...both come with danger.

NYPD criminal profiler Catherine Farrows knew her life would change forever when she committed herself to covert billionaire Thomas Ambrose - and his violent vigilante alter ego, the Black Mask Killer. Together they work to protect the children of New York City and abroad from the predations of the Ganymede Society, a secret cabal of one-percenters who sexually exploit and murder children. Morally-conflicted Catherine has never had to wrestle with her conscience and convictions so much in her life. Neither has she ever been happier...or more in danger.

As Catherine and Thomas's relationship deepens, and they get closer to exposing the members of Ganymede, their plans are suddenly disrupted by a mocking note from an unknown stalker. Mad sniper Cupid knows that Catherine is the Black Mask's lover...and he aims to wound the Black Mask in a way he can't endure, by murdering her.

But as they scramble to uncover the identity of Cupid and take him out before he guns down anyone else, Thomas and Catherine gain unexpected allies among the NYPD and FBI members who get caught in Cupid's crossfire. Angry, protective top cop Brian Andrews and brilliant, courageous FBI agent Jason Leong are there to step in when the duo needs them. But Jason has designs on Catherine...and the Black Mask himself is about to end up a captive of their stalker.

To save him, Catherine must call on her new allies as she prepares to take on aspiring super villain Cupid. This time, it's Tom who needs a masked vigilante's help...and she's the one who must don a mask and prepare to fight.