Kate Mara stars in this US biographical drama directed by Gabriela Cowperthwaite. The film follows young US Marine Megan Leavey (Mara) as she is paired up with an aggressive combat dog, Rex, while serving with the K-9 unit in Iraq. The cast also includes Common, Corey Johnson and Edie Falco. After training Rex, Megan forms a strong bond with her new companion and together they are able to save many lives. However, when they are both injured by an improvised explosive device, their futures are thrown into doubt.