Five years in a foreign prison. He missed his daughter's first steps, her first words, her first bruises. Now he's back. And the people responsible are about to find out — they should never have touched his family.

Detective Sarah Vance is the city's toughest cop, hunting the vigilante 'Ronin.' She comes home to Noah, her clumsy, soft-hearted librarian husband, unaware he is the very assassin she’s hunting—and that he uses her police files to target the corrupt oligarchs she can't legally touch.