The Eagle

“The Eagle” is a lot easier to swallow when you know that the book it’s based on — Rosemary Sutcliff’s “The Eagle of the Ninth,” from 1954 — was intended for young adult readers. That doesn’t give a story license to be dumb, but it does promote a certain leniency toward elements that might otherwise make you roll your eyes. For example, the hero, a Roman soldier looking for a long-lost platoon whose symbol was a bronze eagle, is named Marcus Aquila — and “Aquila” is Latin for “eagle.” His last name matches the thing he’s looking for. In a serious, grown-up historical drama, that would be dopey. Aimed at younger readers, though, it comes across as charmingly simple.

The film version, directed by Kevin Macdonald (“The Last King of Scotland”), has that laid-back, easy-to-watch vibe. It pretends half-heartedly to target adult audiences while keeping the violence toned down enough to stay in the teen-friendly PG-13 realm and letting the dialogue remain unapologetically anachronistic. (“Come on!” Marcus yells to a crowd, urging them to vote in favor of something. “Get your thumbs up!”) Less epic than “Gladiator,” less ridiculous than last year’s “Centurion,” less homoerotic than “Top Gun” (but just barely), this is perfectly acceptable matinee fodder.

Marcus Aquila is played by Channing Tatum, a man who dances well and looks good in a centurion’s costume but isn’t exactly overburdened with personality. It’s the middle of the second century A.D., and Marcus is the new commander of a Roman garrison in occupied Britain. He is a good leader, but he struggles to earn the respect of his men because of a certain family embarrassment: It was Marcus’ father who was leading the famed Ninth Legion when it disappeared, some 20 years ago, never to be heard from again. Look, nobody’s saying Mr. Aquila Senior was bad at his job. They’re just saying he happened to be the one in charge when 5,000 soldiers vanished in northern Britain, that’s all.

Heroically injured in battle, Marcus can no longer fight against the barbaric local tribes that are savagely trying to chase out the Romans, the big meanies. (Seriously, it’s getting to where an empire can’t even invade, conquer, and colonize whomever it pleases anymore!) But after being counseled by his wise old uncle (Donald Sutherland), Marcus hits on another way of serving Rome. He pronounces it thus: “If I can’t win back my family’s honor by being a soldier, then I’ll do it by finding the lost Eagle!” That means heading north, beyond Hadrian’s Wall, into what nowadays we’d call Scotland, in search of the Ninth Legion and/or its bronze emblem.

He is assisted in his quest by Esca (Jamie Bell), a slave boy of the local race whom he saves from being murdered in a gladiatorial arena because he admires his moxie, or possibly his spunk. Esca harbors ill will toward Marcus and the rest of the Romans (what with their being merciless conquerers of Esca’s people and all), but a deal’s a deal, so off they go. Esca can blend in with the locals up north — in fact, he’ll have to pretend that Marcus is his slave — and subtly search for clues about the missing eagle ornament and the men who once carried it.

Speaking of regaining one’s honor, Kevin Macdonald has made more valuable films than this one, notably the documentaries “Touching the Void” and “One Day in September.” Macdonald handles “The Eagle” like a pro, achieving some modest thrills in the action scenes. He is not one to slack off, even on frivolous projects. But you get the feeling he won’t be listing this one near the top of his resume. Tatum and Bell do the male-bonding thing just fine and kick the requisite amount of Scottish arse. You want a movie like this to entertain you without making you feel embarrassed to have bought a ticket, and that’s pretty much what it does.

B- (1 hr., 54 min.; PG-13, a lot of battle violence, nothing terribly graphic.)