The Coen brothers love old movies, and not just the classics. I remember reading an interview where they discussed their affection for “With Six You Get Eggroll,” which even Doris Day’s most fervent fans do not consider one of her best. With “Hail, Caesar!” they pay loving tribute to the final years of the golden era of the Hollywood studios, in part because it gives them a chance to tell a story about change, and choice, responsibility and irresponsibility, and in part because it gives them a chance to play studio heads themselves, overseeing not just one movie but five. And as Orson Welles said, that’s “the biggest electric train set any boy ever had.”

There really was an Eddie Mannix, the MGM executive who had various titles but who was pretty much a full-time fixer. Whether it was a starlet’s nude photos or a male star’s casting couch encounter with a male director, his job was to keep it out of the courts and especially out of the gossip columns and scandal magazines with names like “Confidential.” This was accomplished with bribes, intimidation, and trading of favors. A reputation would be saved by giving the reporter exclusive access or even a juicy story about a lesser star who could be sacrificed to save the day for someone the studio considered a major asset.

The Eddie Mannix played by Josh Brolin works at a studio called Capitol Pictures, but the issue of capital will arise as well. Eddie is under so much stress he goes to confession every day. He is responsible for keeping the entire studio running smoothly, and that begins before dawn, where he extracts an actress from a compromising situation (paying off the cops), and continues on the studio lot. There he assigns an amiable singing cowboy star named Hobie Doyle (a winning Alden Ehrenreich) to put on a dinner jacket and take over the lead in a high-prestige drawing room drama, even though he’s “a dust guy” and his dialog in previous films was pretty much limited to whistling for his horse, Whitey, and “Hold on, there, partner.” Cleaning him up and putting him in a dinner jacket is not a problem, but the intricate drama he is thrown into requires tricky lines like “Would that t’were so simple,” preceded by a mirthless laugh.

Mannix visits the set of a big-budget musical and sees a water ballet out of Busby Berkeley’s wildest dreams. But the star is pregnant but not married (a career-killer in those days). She’s played by Scarlett Johansson with enough wit and brio to power the massive flume of water that lifts her mermaid character up into the sky.

The biggest studio production is the epic “Hail, Caesar,” about a Roman centurion who becomes a follower of Jesus (oddly similar to the upcoming “Risen”). It stars the studio’s most valuable actor, with the manly name of Baird Whitlock (a wickedly funny George Clooney). Mannix thinks his biggest problem is going to be making sure that the movie does not offend anyone in the audience, and in a hilarious scene, he consults with a focus group of clergy, or tries to. But then a real problem arises. Baird Whitlock is kidnapped and being held for ransom by a group that calls itself “The Future.” They are a group led by the most improbable of 20th century scholars, accurately quoted if not accurately portrayed, and supported by…well, no more spoilers here.

It’s flat-out funny, whether you know the history or not, and I left wishing for a quadruple feature that would include all of the films we see in production (well, maybe not the other “Hail, Caesar”). What keeps it buoyant, even effervescent, is the pure affection for films and filmmaking in every one of what in the pre-digital days we used to call frames. (We see them up close and personal in a hilarious scene with Frances McDormand as an old-school film editor.) The movie touches lightly on issues of story-telling and the inherent chaos and frustration of trying to balance art and commerce, plus the skills and needs of a large group of people. But the love story here is between Mannix, as a stand-in for the writer/directors, and the movies.

Parents should know that this film includes kidnapping, out-of-wedlock pregnancy and paternity issues, some sexual references, drinking and references to alcoholism, and smoking.

Family discussion: Which real-life characters inspired this movie? Should Eddie take the job offer?

If you like this, try: some of the movies that inspired this one like “Million Dollar Mermaid,” “Anchors Aweigh,” “My Pal Trigger,” and “The Robe”