In ancient Britain, a Roman soldier (Channing Tatum) and his slave (Jamie Bell) venture into the wild highlands to retrieve the eagle standard of the soldier’s father’s legion, lost (like the legion itself) 20 years earlier. Jeremy Brock’s script (from Rosemary Sutcliff’s novel) begins well, but Brock evidently didn’t read past page 42: The movie morphs into a sort of Celtic Last of the Mohicans, then a risible variation on The Over-the-Hill Gang. In a bow to political correctness and the star’s limitations, Sutcliff’s sensitive, resourceful Roman hero becomes haughty, impulsive and rather stupid. At least director Kevin Macdonald keeps the action moving and in focus. Viewers who haven’t read Sutcliff’s book may find the movie passable enough; those who have will be appalled (though hardly surprised).