In 2008, Lee meets Kate Macer in a bar. They keep in touch, and a few years later, he finds her broken after being used and threatened by hitman, Alejandro, so he brings her home. She wants to be an Expendable, and against his better judgment, Lee trains her. When she starts dating another Expendable, Lee has 2 choices: tell her how he feels, or let her go.

Kate Macer left her past behind her until her young protege, Mei, goes missing during a case, throwing Kate back into the world of the cartel. Mei's friend, Luke Wright (former assassin), is determined to find her and gets put under Kate's supervision, much to her annoyance. Elsewhere, Alejandro stumbles upon a lost and disoriented young woman (Mei), trying to get home safe.

Like she was told, Kate Macer moved to a small town where she joins the local law enforcement. Then she meets Phil Broker, an ex cop who moved there to escape a dangerous biker gang. Kate finds herself intrigued by Phil, and they soon become close to each other. When an incident at the public school becomes a hostage situation, it's up to them to save everyone inside.