Sam (Karen Gillan) was only 12 years old when her mother Scarlet (Lena Headey), an elite assassin, was forced to abandon her. Sam was raised by “The Firm”, the ruthless crime syndicate her mother worked for. Now, 15 years later, Sam has followed in her mother’s footsteps and has become a ruthless contract killer, as efficient as she is loyal. She uses her “talents” to clean up the Firm’s most dangerous messes.
But when a high-stakes job goes wrong, Sam must choose between serving “The Firm” and protecting the life of an innocent 8-year-old girl: Emily (Chloe Coleman). Sam has only one chance to survive: reunite with his mother and her deadly partners: “The Librarians” (Angela Bassett, Michelle Yeoh and Carla Gugino).
These three generations of women must learn to trust each other, confront “The Firm” and its army of minions, and confront all those who stand in their way.