Film zasnovan na istinitoj priči o mladoj pripadnici Marinaca, čija je jedinstvena obuka i povezanost sa njenim borbenim psom spasili mnoge živote vojnika u Iraku. Tokom službe, Megan i Rex učestvovali su u više od 100 misija, dok se nije desila sudbonosna eksplozija.
Based on the true life story of a young Marine corporal whose unique discipline and bond with her military combat dog saved many lives during their deployment in Iraq. When she is assigned to clean up the K9 unit after a disciplinary hearing, Leavey identifies with a particularly aggressive dog, Rex, and is given the chance to train him. Over the course of their service, Megan and Rex completed more than 100 missions until an IED explosion injures them, putting their fate in jeopardy.