Modesto Women's Book Club

Hi page turners!
This month's pick is from Ann-Marie!
Title: Killers of a certain age
Author: Deanna Raybourn
Genre: contemporary action-thriller!!!
Quick summary: Billie, Mary Alice, Helen, and Natalie have worked for the Museum, an elite network of assassins, for forty years. Now their talents are considered old-school and no one appreciates what they have to offer in an age that relies more on technology than people skills.
When the foursome is sent on an all-expenses paid vacation to mark their retirement, they are targeted by one of their own. Only the Board, the top-level members of the Museum, can order the termination of field agents, and the women realize they've been marked for death. What will they do?!?!?!?!