A new assignment forces a top spy to team up with his football hooligan brother. Nobby (Sacha Baron Cohen), a sweet but dimwitted English football hooligan, has everything a man from the poor fishing town of Grimsby could want, including 9 children and the most attractive girlfriend in the Northern England (Rebel Wilson). There's only one thing missing: his little brother, Sebastian (Mark Strong), who Nobby has spent 28 years searching for after they were separated as kids. Nobby sets off to reunite with Sebastian, unaware that not only is his brother MI6's deadliest assassin, but he's just uncovered plans for an imminent global terrorist attack. On the run and wrongfully accused, Sebastian realizes that if he is going to save the world, he will need the help of it's biggest idiot.