Garrett Hedlund’s Thomas sits across the table from Oscar Isaac’s Jack.

Each man pretty much would like the other one to die, preferably as soon as possible — but that doesn’t mean there isn’t room for philosophical discussion.

“Do you believe in the duality of man?” asks Jack.

“No,” replies Thomas. “I believe in infinite complexity.”

“Oh. How many more is that than duality?”

“A lot.”

Not the kind of loony-intellectual, dark and oddly funny dialogue you’re gonna get in your “Ride Along 2” or your “Ridiculous Six,” am I right?

William Monahan, the Oscar-winning screenwriter of “The Departed,” is the writer and director of “Mojave,” the first great film of 2016, featuring the first great performance of 2016. Oscar Isaac, on a brilliant winning streak the last couple of years with “A Most Violent Year,” “Ex Machina,” “Show Me a Hero” and “Star Wars: The Force Awakens,” delivers such masterful work that the minute this movie was over, I wanted to watch it again so I could soak in the greatness of the performance.

Garrett Hedlund is outstanding as Thomas, who has been a famous actor since he was a child and is in the middle of some sort of deep and perhaps permanent existential crisis.

Self-destructive to the verge of suicidal, Thomas finds himself deep and high up in the Mojave desert, where he encounters Isaac’s Jack, a gun-toting drifter who’s dressed as if he’s in a summertime version of “The Hateful Eight,” sports alarmingly horrible teeth and keeps calling Thomas “brother,” even as they verbally spar and consider the very real possibility of extreme violence exploding at any moment.

(Jack calls everyone, even a puppy he encounters, “brother.” Never has such a term of endearment sounded so menacing.)

Terrible things happen in the desert, and more terrible things happen once Thomas returns to his life as a tortured movie star, with Jack stalking him. One or both of these men is capable of cold-blooded murder. Jack is such a monster Thomas openly wonders if Jack is actually Satan — but Thomas is no angel either.

“Mojave” has a little bit of “Cape Fear” in its blood. Thomas can’t shake Jack, and his efforts to confront and stop Jack often only make things worse.

Mark Wahlberg, Monahan’s buddy from “The Departed” and “The Gambler,” has a funny extended cameo as a bigshot producer, who doesn’t even pretend to care about Thomas’ claim he’s being stalked and is in deep trouble. Walton Goggins is terrific as Thomas’ agent, who barely tolerates his star client’s nonsense. (“Do you have any other rhetorical questions you want me to answer?” he says with exasperation at one point.) Dania Ramirez does fine work as a detective trying to solve the murder of a fellow police officer.

Mostly, though, “Mojave” is about the deadly game of cat and mouse between Thomas and Jack, neither of whom seems all that troubled if the game ends with one or both dead.

When Jack sidles up to an actress who is involved with Thomas, offering her a flower and passing himself off as a producer, it’s a chillingly effective scene. Even when it’s just Jack and that cute little puppy onscreen, Jack has some great and funny and frightening lines.

“Mojave” isn’t the best-looking film in the world. Monahan the director seems to enjoy shooting in the dark — whether we’re in the desert in the middle of the night, or in a bar where the simple act of a waiter offering to bring Thomas and Jack drinks turns into a philosophical discussion. Jack is so slippery and mysterious he seems to be hiding in the shadows, even in the middle of the day. In fact, until Thomas and Jack were out of that desert and Jack started interacting with other characters in the film, I wasn’t entirely certain Jack wasn’t a figment of Thomas’ imagination.

This movie soars on the strength of the screenplay. Monahan gives Hedlund and in particular Isaac dozens upon dozens of rich, intricate lines, and they’re both up to the task and then some. Isaac is an actor who is not afraid to go big or go home, but in “Mojave,” his finest moments are relatively quiet and sublime. Every inch of his performance is pure excellence.

[s3r star=4/4]

A24 presents a film written and directed by William Monahan. Running time: 93 minutes. Rated R (for language and some violence). Opens Friday at AMC Loews Streets of Woodfield 20 and on demand.