Introducing “Dungeons & Dragons: Honor Among Thieves,” the lavish hyperkinetic popcorn fairy tale that kicked off SXSW this evening, the film’s co-directors, John Francis Daley and Jonathan Goldstein, told the audience that they had designed the movie to appeal to hardcore D&D players — and also to those who know absolutely nothing about the game. This came as a relief to me, since what I know about Dungeons & Dragons you could put on the head of a…well, I know so little that I can’t even come up with a proper D&D reference with which to spin that cliché.

The filmmakers were being honest. “Honor Among Thieves” is built on the edifice of D&D lore, packed with totems and characters and Easter eggs that fans of the legendary role-playing game will drink in with a connoisseur’s delight. But for those, like me, who have spent their lives avoiding anything to do with Dungeons & Dragons, the film is eminently comprehensible and, in its you’ve-seen-it-before-but-not-quite-this-way fashion, a lot of fun.

The game, which has been around for 49 years, was ahead of its time in how it anticipated our collective immersion in mystic adventure fantasy and the intensity of role-playing that went along with it. In the ’70s, D&D was like Comic-Con as a table game — an abstract geek-brainiac’s version of cosplay. The film turns the table, presenting itself as an homage to all the movies that, in hindsight, can be seen as a gleam in the eye of Dungeons & Dragons; it also taps into the fantasy worlds that the game itself drew upon. “Honor Among Thieves” is like a mash-up of “The Lord of the Rings,” “The Princess Bride,” “Star Wars,” “National Treasure,” a medieval “X-Men”…and “Gladiator”! It’s at once cheesy and charming, synthetic and spectacular, cozily derivative and rambunctiously inventive, a processed piece of junk-culture joy that, by the end, may bring a tear to your eye.

It’s set in some blockbuster FX version of the Middle Ages, but Chris Pine, acting with the anachronistic contempo Bogart-meets-Don-Johnson-as-grizzled-yuppie charisma that made him so perfect as Capt. James T. Kirk, grounds the film in something loose and aggro. He plays Edgin Darvis, a fallen member of the Harpers — think of them as secret knights — who’s a thief, a liar, and a rogue, but one with a valiant heart. Edgin’s wife was murdered, leaving him to raise their young daughter, Kira (Chloe Coleman), which he has done with the help of his comrade, Holga, a tattooed barbarian played by Michelle Rodriguez with a gruff companionable street-tough sinew.

Kira, however, has come under the spell of Forge Fitzwilliam (Hugh Grant, chewing voraciously on every line), a scoundrel who rules over a walled city, and has convinced Kira that he can be a better dad to her than her own duplicitous father. Edgin wants to put his family back together, and if he can lay his hands on the Tablet of Reawakening, he’ll have the ability to bring his wife back to life and restore all that was lost. But the Tablet is locked up in a vault in the city, and he needs to find the Helmet of Disjunction — which can stop time — to do it. Are you with me?

“Honor Among Thieves” keeps introducing rules and gambits that interlock with pleasing logic but, as often as not, turn out to be MacGuffins. Yet they do their job — they seduce us, for a few scenes, into seeming as if they matter, at which point the film is only too happy to move on. Daley and Goldstein work with a precision that satisfies our inner megaplex classicist, yet it’s part of the film’s design that it never stops throwing things at us.

As Edgin forms a fellowship with such winningly offbeat characters as the insecure sorcerer Simon (Justice Smith) and the shape-shifting druid Doric (Sophia Lillis), “Honor Among Thieves” becomes a gallivanting magic-trick action movie with a dragon so pudgy the characters make a joke of it, an undead cult of Red Wizards who rule their minions with billows of crimson smoke like something out of “The Wizard of Oz,” and a scene of crowd-pleasing macabre cheekiness in which old grey skeletal corpses are raised from the dead so they can be asked five questions, at which point they collapse back into oblivion. The dialogue in a scene like this one has a precocious snap. The script is by Daley, Goldstein, and Michael Gilio, who invest each encounter — even if it’s with a corpse — with a charge of ego.

That said, there’s enough snark and visual zap on display that we may feel like we’re gorging on candy corn, and that we’re hungry for something a little more soulful. It arrives, in the person of Regé-Jean Page, who shows up as Yendar, who is noble in such an old-fashioned stoic corn-dog way (he can’t process irony, let alone a phrase like “son-of-a-bitch”) that he lends the movie the note of romantic valor we want. Page acts with a dark-liquid-eyed savoir faire that’s delectable, and for a while he and Pine become an ace comedy team: Yendar the man too suavely heroic to crack a joke, Edgin the one who makes a joke out of everything, including Yendar’s nobility.

It’s Yendar who leads them to the towering stone catacomb where the Helmet of Disjunction is to be found. There’s a terrific sequence in which he recites the elaborate rules for how to walk over a stone bridge, which go out the window the moment Simon takes a wrong step. But then Simon — this is exactly how the movie rolls — just happens to pull out a magic walking stick that creates a portal you can slip through 500 feet away. Cool!

There’s an intricacy to the staging of “Honor Among Thieves” that helps balance out the roller-coaster derivativeness of the plot. We go with it, even as we know we’re gorging on a succulent overdose of fantasy dessert. The gladiatorial battle inside a maze at the climax is sensationally well done, from the panther with Venus-flytrap tentacles to the treasure boxes along the way to the giant cubes of Jell-O that help save the day. The monster at the end? To me that was one demon too many. But no matter. “Dungeons & Dragons: Honor Among Thieves” should be a major hit, because it knows how to tap into our nostalgia — not just for a game, but for the entire fantasy culture it helped to spawn. It’s the movie itself that’s role-playing.