Kill For Me, Kill for You by Steve Cavanagh

One dark evening on New York City's Upper West Side, two strangers meet by chance. Over drinks, Amanda and Wendy realize they have much in common, especially loneliness and an intense desire for revenge against the men who destroyed their families. As they talk into the night, they come up with the perfect if you kill for me, I'll kill for you.

In another part of the city, Ruth is home alone when the beautiful brownstone she shares with her husband, Scott, is invaded. She's attacked by a man with piercing blue eyes, who disappears into the night. Will she ever be able to feel safe again while the blue-eyed stranger is out there?