Inferno marks the third movie from director Ron Howard and star Tom Hanks based on the popular novels by Dan Brown about Harvard professor and symbologist Robert Langdon. They’re all varying degrees of not great — and Inferno is easily the worst of the bunch — but what’s particularly galling about this franchise are the years Howard and Hanks, two of our most dependable filmmakers, have wasted on it. Together they’ve made Splash and Apollo 13; separately their credits include Cinderella Man, The Paper, Saving Private RyanCaptain Phillips and so many others. How many great movies could they have made, as a team or as individuals, if they hadn’t committed their talents to these cruddy thrillers?

It doesn’t help that Howard and Hanks are both miscast for their roles adapting Brown’s material. Hanks is the consummate everyman, and Howard is a consummate director of movies about everymen; warm comedies and historical dramas rooted in rich characters and the triumph of the underdog. Brown’s books are nonstop paranoid chases featuring a talkative bookworm. Howard doesn’t have the intensity for breathless thrillers and Hanks can’t draw on his warmth or ordinary decency as Langdon. Even after three of these movies, they still haven’t found their footing. In fact, they seem less sure of themselves with each new installment.

Inferno, the first Brown adaptation since 2009’s two-time Teen Choice Award nominee Angels & Demons, ratchets up the stakes from the previous movies but maintains their basic conceit and structure: Brilliant Langdon is out of his depth and on the run in a foreign country, solving a series of historical riddles on the trail of some all-important MacGuffin. In this case, that’s a deadly virus engineered by mad billionaire Bertrand Zobrist (Ben Foster), who believes the human race is headed towards extinction if drastic steps aren’t taken to curb overpopulation.

He engineers a killer germ, hides it somewhere on the planet, and then commits suicide so that no one can stop it from being unleashed in a couple days. If you’re a deranged murderer who truly believes half the world’s population must die, why would you put your doomsday bug on a timer so that someone could potentially prevent its dispersal instead of just, I don’t know, dumping it directly into a reservoir or something? You wouldn’t, but hey, he’s the brilliant bioengineer and I’m the guy who spent his Tuesday night watching Inferno so maybe I’m not the most qualified person to judge someone’s life choices.

After Zobrist’s suicide in the prologue, Howard reintroduces Langdon, disoriented and concussed, in a Florence hospital. His doctor, Sienna Brooks (Felicity Jones), tells him a gunshot wound to the head gave him partial amnesia; he can’t remember how he got to Italy or why he’s there or who attacked him, so when the police arrive and start spraying the hospital with bullets, he and Dr. Brooks go on the run. Inside a hazmat vial, they find a Faraday pointer that projects an image of Botticelli’s Map of Hell, inspired by Dante’s Inferno. This particular Map of Hell has been rearranged and changed in subtle ways; the changes provide Langdon and Brooks the clues they need to start locating Zobrist’s virus.

All the while, Langdon keeps experiencing hallucinations, including a woman with her head covered by a shroud, men covered in festering boils, and oceans of blood. Howard uses point-of-view editing, out-of-focus close-ups, and quick flashes of nightmarish imagery to mimic his hero’s muddled point-of-view. It’s almost too effective; the results are more unpleasant than scary. Howard also repeatedly fills the frame with lots of extras; Hanks and Jones pushing their way through crowds, or intimate conversations staged in front of, or in the middle of, masses of humanity. Inferno is deliberately overcrowded, a subtle and effective touch that suggests that while Zobrist’s methods may be monstrous, his ideas might have merit.

Here is an idea, though, that doesn’t have merit: Making Langdon and Brooks and everyone else they meet talk to each other like morons. One of the little pleasures of Dan Brown’s work are the curious stranger-than-fiction details of art and religious history crammed into the margins. Screenwriter David Koepp’s script clumsily shoves these factoids into the mouths of the characters, which leads to absurd dialogue exchanges where people explain basic concepts for the benefit of the audience. Why would the curator of a museum in Italy describe what a death mask is to a Harvard professor of history and symbols whom she’d met before? Even worse, a few scenes later we learn that the curator met Langdon previously when he came to look at ... a death mask! Who is the amnesiac here, him or her?

The Da Vinci Code wasn’t Da Vinci, but it was an actual movie with texture and characters. Inferno is dumbed down to a shocking degree. Every time the characters stumble on a clue, they look at it and read it aloud; when they arrive at the next clue, they repeat the old one and it flashes onscreen. It’s as if the movie was designed for viewers who aren’t paying attention; someone playing Candy Crush on their phone or doing their taxes with Inferno on in the background would be able to follow along without actually looking at the screen. Audiences deserve better than this. And Howard and Hanks are certainly capable of better than this.

Additional Thoughts

-That terrible scene where the curator explains death masks to Langdon leads to a scene that is arguably even stupider, where the mask is missing and they all go to the security office to watch the security footage and see what happened, and it turns out ... Langdon stole it! A priceless work of art went missing for a day and no one noticed until the same guy came back and wanted to see it? Everyone in this museum should be fired.

-The story doesn’t leave much room for the actors to flex their muscles, but Irrfan Khan gets a couple of nice scenes as the head of a mysterious organization with ties to Zobrist. Not too many men could pull off “Guy Who Explains Convoluted Plots at Length and Also Carries Ornate Knives in Holsters Hidden in His Sleeves” with a straight face, but he does.