Our hero got a call from his ex-lover two days ago, after a furtive note telling him to be at a certain phone booth at a certain time. She sounded like she was in trouble, so he went looking for her; asked around; kept his eyes open. And now he's found her. Dead. Face-down in a reservoir, her blonde hair trailing in the rainwater runoff. He's shaken, but he knows what he has to do: He's going to find out who's responsible. He's going to find out why they killed her. He's going to see that justice – or something like it – is done. He walks away from the body, sad but ready. He's going to have to plumb the local underworld. He's going to have to ask ugly questions. He's also going to have to come up with an excuse for the Assistant Vice-Principal about why he won't be in class for the next few days. ...

Brick, written and directed by Rian Johnson, is already being called many things: Hammett goes to high school; a teen noir; a distorted trip through two different genres, as if John Hughes directed The Maltese Falcon. All those things are right (or glib enough to be quotable, which is almost as good), but let's also cut to the chase: The first thing you need to know about Brick is that it's hands down the first truly great film of 2006, one worth seeing and seeing again and actually thinking about, with sharp, snappy dialogue giving it a lustrous gloss, and carefully-drawn, achingly human characters putting real weight and power under the sheen. What Johnson's done with Brick is something akin to taking two old pieces of wood – caked with years of dust and shoddily-applied paint, layers of uneven age-dulled wax, cheap veneer and hastily-applied stain – and banging them against each other so hard and so precisely that all the cover-up and concealment fall away revealing the true beauty and grain of each piece so we can see them both as new.

Our hero, Brendan, is played by Joseph Gordon-Leavitt, a smart, withdrawn kid with a mop of unruly hair and glasses; he used to go out with Emily (Emille DeRaven), but she broke up with him and fell in with a bad crowd. Between her phone call and the discovery of her body, Brendan scours the school looking for answers about what she's up to, asking The Brain (Matt O'Leary) about her crowd: "Who's she eating with?" Checking in with the stoners, the drama queens, the football heroes. He doesn't find her until he finds her dead. And Brendan may be no more than 16, 17 years old, but a man's got to do what a man's got to do.

One of Brick's many pleasures is how it doesn't spell everything out for audiences; it teases you along, daring you to catch up. It turns out that Brendan's done something like this before, handing a delinquent and dope dealer named Jerr over to school authorities. When the Assistant Vice-Principal (Richard Roundtree, note-perfect) wants Brendan to tell him what's going on now, because "You've helped this office out before," Brendan's reply is classic, cagey noir bravado: "I gave you Jerr to see him eaten, not to see you fed." But if snappy dialogue were all Brick had, it'd be a fairly empty exercise in style, old goods in new packaging. Part of what makes Brick so good is Johnson's willingness to let his script be with his characters – to give them real feelings and the time to express them, to have their inner emotional choices drive their external actions. Emily is not just a plot device to Brendan; thanks to Johnson's writing and direction and Gordon-Leavitt's performance, she's not just a plot device to us, either.

And at the same time, none of the character moments and grace notes in the performances distract from the snap, the zing, the appeal of Brick's gutsy central conceit of uniting crime fiction and teen drama: The warmth actually brings out the cool, and vice-versa. Johnson's understanding of noir style isn't shallow; it isn't overly studied, either. Brendan's two foremost noir hero characteristics are that he can take a hell of a beating and spends a lot of time unconscious. A lot of movies that claim to pay tribute to old-school crime fiction get the look of it right and the feel of it wrong. Brick avoids the look – Brendan wears ratty hoodies and army jackets, the kind of stuff you wear as a teen so you can disappear into it, not a trench coat or a suit – and that means Brick can focus on feel. A film like Kiss Kiss Bang Bang or the wildly over-praised Sin City uses noir language and style to craft fun, hollow power fantasies about invincibility. Brick uses noir language and style to craft a real, riveting moral parable about mortality. When you were a teen, being a teen felt like a matter of life and death. Well, it's like that in Brick. Just a little moreso.

Leavitt is in pretty much every scene of Brick, and it's a virtuoso performance – emotionally rich but stylistically juicy, with the nutrition and sizzle of a great steak dinner with all the sides done just right. The supporting actors are also cast in style of classic crime films: Find actors who look like what they play, from Lukas Haas's turn as crime lord The Pin (who, The Brain explains, "... is really old ... like, 26 ...") to Nora Zehtener's Laura Dannon, who may (in classic femme fatale fashion,) be Brendan's best ally or worst enemy. Haas is intimidating and intimidated, a criminal who knows how fragile his empire is; Zehtener's allure is the tight, shiny wrapper around a core of secrets and lies.

But this is Johnson's film, and it's one of the most accomplished writing-directing debuts in recent memory. You can instantly discern that, like many first-time writer-directors, Johnson has honed and shaped his script with skill and patience and dedication. You can also instantly discern that, unlike many first-time writer directors, Johnson is neither afraid of stylish camera work nor distractingly addicted to it. Brick has plenty of visual flourishes, nice cuts, tricky little visuals and deft visions. The difference between Brick and something like Lucky Number Slevin is that the visual flourishes, nice cuts, tricky little visuals and deft visions come out of the story, and help move it forward.

If a filmmaker is lucky, and talented, then their first film serves as their introduction: It makes you eager to see what else they're capable of, makes you anticipate their next film fiercely and avidly. It's a rare kind of debut film that creates that kind of impression. Even more rare is the debut film that makes you look forward to the next, better-financed, better-backed, better-promoted film from a filmmaker and stands up as an impressive, exciting and moving piece of work in its own right. Those films are like a handful of diamonds scattered over a mile-long section of beach; Brick is one of them.