Alex by Maddie Wade

As second in command of Eidolon, Alex Martinez is a ghost who lives in the shadows. Despite doing a job he loves, Alex has never forgotten the love of his life—the woman he proposed to at eighteen—whose disappearance changed the course of his destiny.
Evelyn Garcia’s dreams were ripped away from her one dark, sultry Cuban night when she was just a teen. She’d fought the horrors she’d witnessed by becoming the feared and deadly assassin Siren. Using seduction, she gets men to spill their sick, twisted secrets before exacting revenge.
When Alex comes face to face with Evelyn again, he witnesses her killing a man in cold blood. Unable to reconcile the woman from his memories with the cold-blooded killer she is now, Alex vows to have nothing to do with the woman he’d once loved. Then he’s handed a new contract—Siren has a kill order on her, and Alex must carry it out.
Can Alex overcome his anger and feelings of betrayal and save Siren, or will he follow orders and terminate her?
A race against time is on, as Alex and Siren battle to discover the truth behind the order and save both their lives.