rated PG-13

In Hollywood, facts and bad actors never get in the way of a good story, though they can ruin that story’s momentum.

That’s exactly what happens in “The Eagle,” the latest movie to tackle the enduring mystery of the Roman Ninth Legion that went “missing” in Roman-occupied Britain. The film gives the burden to Channing Tatum, a barely-there leading man whose range extends from “hunky” to “angry,” with occasional forays into “sad.” The movie should be epic, an old-school tale of honor, duty and the bonds of brotherhood, but with the underwhelming Tatum at the front and a weak script, “The Eagle” lands with a dull thud.

Even though historical records have shown the Ninth didn’t really disappear in the wild glens of ancient Scotland, the story holds plenty of promise, enough that “The Eagle” is the second film within a year to tackle the subject. Neil Marshall’s 2010 “Centurion” told the tale of the Ninth but cast the Romans as the underdogs, fighting their way out of a land in which they shouldn’t have been in the first place. Kevin Macdonald’s “The Eagle” is a little more straightforward—at least, any hints of complexity or depth are promptly dismissed. 

“The Eagle” picks up in 140 A.D. It’s been 20 years since the Ninth Legion disappeared beyond Hadrian’s Wall and the legion’s standard—a golden eagle—remains missing, a symbol of defeat for the empire. Marcus Aquila (Tatum) arrives in Britain to command a garrison of centurions. His father commanded the Ninth, and Aquila hopes to regain his family’s honor.

The local tribes remain hostile to the Romans, though, and just as Aquila scores a major victory, he’s wounded in battle and drummed out of the army. He convalesces with his uncle (played with easy charm by Donald Sutherland), saves the life of the doomed slave Esca (Jamie Bell), and learns that the golden eagle has been spotted among the Seal People, a savage tribe that lives far beyond the borders of the known world.

Esca is the key to Aquila’s plan. He’s a disgruntled Celt who owes a debt of honor to Aquila for saving him. It turns out he is also key to “The Eagle.” While Tatum looks beefy and bewildered, Bell brings a lot to his role. Esca is everything Aquila isn’t: wiry, shifty, crafty, and truly conflicted about Rome’s presence in Britain. Bell captures all the contradictions and shifts in Esca’s personality, and without him, “The Eagle” would be an utter loss.

Macdonald and screenwriter Jeremy Brock seem at a loss about what to do with the movie. Aquila talks a lot about duty to Rome and honoring his family, but Rome and Roman rule seem lousy (the first thing Aquila does after arriving at the garrison is order the latrines to be repaired), and Aquila’s father is nothing but gauzy flashbacks and vague ideas. That Aquila must reinvade a land from which the Roman army was already expelled in order to save face is a juicy contradiction, but one that Macdonald and Brock don’t mine.But nor do they mine the more conventional stuff—daring battles, heroic duels and other swords-and-sandals standards. “The Eagle” is based on Rosemary Sutcliff’s 1954 novel, “The Eagle of the Ninth,” a boy’s adventure story primarily concerned with derring-do. The film’s few action sequences are frantic but well choreographed; unfortunately, they’re spaced far apart, and too much time is spent with Tatum as he tries to wrestle with his limited emotive states. 

One of the best bits comes late in the film, when Aquila and Esca, deep behind enemy lines and the “guests” of the Seal People, witness a frenzied tribal coming-of-age ritual. Aquila catches site of the eagle and goes into a frenzy, unaware he’s surrounded by 100 hostile warriors. It’s wonderfully tense and forbidding and drives home the predicament that Aquila and Esca are embedded in like a spear. If only the rest of “The Eagle” was so sharp.