Horrible Histories: The Movie — Rotten Romans.

Brainy Roman teenager Atti is always coming up with schemes, but one ultimately goes too far, angering Emperor Nero. As punishment, the lad is exiled to the cold wet province of Roman Britain on the fringe of the Roman Empire. Whilst there, Atti is captured by—and eventually befriends—Orla, a feisty Celt. When he's returned to his regiment, he's horrified to find himself pitted against Orla and her tribe at the Boudican revolt's Battle of Watling Street.