The film opens in an FBI operation to catch a nearly untraceable, internationally-known terrorist, named Miles Jackson (Aidan Gillen). New Orleans Police Officer Danny Fisher (John Cena) and his partner bump into the getaway car of Jackson and his Fiancée (Taylor Cole). After Danny chases the car on foot, he manages to stop them. Jackson's girlfriend is, however, killed, when she is struck down by a truck after trying to make a run for it. A year later, and Danny and his partner have been promoted to detectives. Jackson has escaped prison and planned his revenge on Fisher in a game he calls "12 Rounds". He kidnaps Fisher's girlfriend Molly Porter (Ashley Scott) and forces him into a series of dangerous games, carefully plotted throughout the streets of New Orleans. Fisher struggles to keep focus while the obvious ticking clocks and crude consequences that accompany each one of the "rounds" do their best to derail him from rescuing the love of his life before it's too late.