WARNING: SPÖILERS

Despite its calm, sympathetic main character, an investigative journalist named Mikael Blomqvist (Michael Nyqvist), it’s hard, as a man, to walk out of “The Girl with the Dragon Tattoo” and not be disgusted with your gender.

Of course I’m one of the few people who walked into the movie not knowing the story. “Dragon Tattoo” is based upon the first of three books, the Millennium trilogy, that journalist Stieg Larsson wrote before he died in 2004. Worldwide sales of these books have now topped 20 million, while the second in the series, “The Girl Who Played with Fire,” became the first translated work since Umberto Eco’s “The Name of the Rose” to top The New York Times bestseller list. The film, with little help from the U.S., has grossed nearly $100 million worldwide, and it’s particularly big in Denmark, where, from a population of 5.4 million, US$17 million has been made (a ratio that if applied to the U.S. would mean a domestic box office take of $957 million), and while I was aware of the phenomenon, I wasn’t aware of the story. I certainly didn’t know the original, Swedish title contains no reference to either girls or dragon tattoos. It’s “Män som hatar kvinnor”: “Men Who Hate Women.”

The movie, indeed, opens with a man with a knife. But he’s a benevolent man, an old Swedish industrialist named Henrik Vanger (Sven-Bertil Taube), who is using the knife to cut open a package. It contains a flowery white plant under glass. He looks at it, sits down at his desk, and weeps.

These early scenes can be confusing for neophytes because they contain three separate storylines: there’s Vanger and that flowery white plant; there’s Blomqvist, a crusading journalist for a progressive magazine, “Millennium,” who is convicted of libel against another industrialist; and there’s the titular character, the girl with the dragon tattoo, Lisbeth Salander (Noomi Rapace), whom we first see, hunched and hooded and seemingly hunted, walking through Swedish subways. How do these characters connect?

Turns out Vanger has hired a research company that employs Salander, a computer hacker, to look into Blomqvist’s life. She does, during his trial and conviction, and comes away with her own conviction that Blomqvist is “totally clean.” She’s also intrigued by him—in the way that she’s intrigued: from a distance—and continues to spy on him after the job is done.

Vanger then hires Blomqvist, who has six months before his prison sentence starts, to look into a case that has haunted the old man for 40 years. In September 1966, his beloved niece, Harriet Vanger, whom we see in a beautiful black-and-white portrait, and who was Blomqvist’s babysitter back in the day, disappeared from Hedeby Island, the site of the Vanger estate. Everyone assumes she’s dead. Henrik assumes someone in his family killed her, and, on his birthday, sends him a framed flower, as Harriet used to do, to taunt him.

The Vanger family is certainly a piece of work. Two of Henrik’s brothers were Nazis: Gofffried, Harriet’s father, who, in 1965, fell into a nearby lake and died, and Harald, mean and rotten, who still lives on the estate.

Two other Vangers live on Hedeby as well: Gottfried’s son (and Harriet’s brother), Martin, who had once been a member of Hitler Youth, but is now older, jollier, and offers Blomqvist 21-year-old malt whiskey; and Harald’s daughter, Cecilia, who offers Blomqvist her bed.

In Stockholm, meanwhile, Lisbeth, still hacking Blomqvist’s computer, is forced to undergo a change in guardians. Since she’s 24, of legal age, I assume guardians in Sweden are similar to parole officers in the U.S. but with legal degrees and more power. Her new guardian, Nils Bjurman (Peter Andersson), turns out to be no guardian at all. Initially he just seems like a dick: He takes greater control of Lisbeth’s bank account and her comings and goings. Then he asks her questions about sex. Then he forces oral sex on her. When she shows up at his place one evening because she needs emergency money, he punches her, handcuffs her to his bed and rapes her. At this point we already know Lisbeth is smart and tough so we’re a little disappointed she gets to this point—realizing she’s trapped, there’s something almost feral in her reaction—but we’ve also seen the small red light in her purse and assume she’s taping the whole, horrible event, which she is. The next time they meet, also at his place, she turns the tables. She tasers him. When he awakes, naked and handcuffed on the floor, she shows him the tape, lists her demands (basically: stay out of my fucking life), then sodomizes him with a dildo and tattoos the following words on his chest and stomach: “I’m a sadist pig and a rapist.”

These are tough scenes to watch, particularly the rape, and at some point I wondered how much of the subplot was necessary. What does it have to do with Harriet Vanger? Couldn’t the filmmakers have excised it cleanly? Answers: “Not much” and “Yes.” Yet I’d still keep it. The subplot complements Larsson’s overall theme—men who hate women—and gives us a clearer view of the title character. This is someone you do not fuck with.

Back on Hedeby Island, Blomqvist rummages through 40-year-old evidence. There’s film footage of a tanker accident on the day she disappeared. (Is that her in the window of a building? Talking to someone? Already looking ghostly?) There’s a newspaper photo, that same day, of Harriet in the crowd at the annual Children’s Day parade, looked to her left, seemingly stunned, while everyone else is looking to their right. (“What are you looking at?” Blomqvist asks the photo.)

Then there’s Harriet’s diary. On the back page, Harriet has listed five sets of names/initials and numbers, such as “Magda 32016” and “BJ 32027.” But they don’t correspond to names anyone knows or numbers that have ever been listed. What are they?

It’s up to Lisbeth, still hacking Blomqvist’s computer, to decipher them, and it’s a deciphering reminiscent of “The DaVinci Code.” (Just as the ghostly portrait and diary recall “Twin Peaks.”) The numbers are Bible verses, all from Leviticus, the third book of the Pentateuch. “32016,” for example, stands for Leviticus 20:16:

“If a woman approaches any beast and lies with it, you shall kill the woman and the beast; they shall be put to death, their blood is upon them.”

The other verses are similarly cheery: burned with fire, cut to pieces, stoned to death. Lisbeth anonymously emails Blomqvist these answers, but he tracks her down, and the two wind up working together on Hedeby. The names and initials, they realize (too quickly), correspond to women who were killed, in the manner articulated in the Bible verses, at different periods: 1949, 1954, etc. But who did the killings? A big hint: All the murdered women were Jewish.

Up to this point we’ve mostly seen Lisbeth by herself, high-strung and tight-mouthed, but it turns out she’s much the same working with Blomqvist. Instigating a sexual relationship doesn’t open her up, either; it reveals how closed-off she is. She’s intimate without intimacy. Something about her suggests a wounded animal, or an animal that was once abused and is now forever skittish and ready to strike back. She also has a kind of super power, a photographic memory (an unnecessary addition: she’s fascinating without it), but when Blomqvist casually mentions this to her, she flinches, startled, and he has to calm her down. He says he didn’t mean anything by it. He says he wishes he had a photographic memory. In her silence is a kind of response: No, you don’t. Or: There are some things better forgotten.

“Dragon Tattoo” is directed by Niels Arden Oplev, a Danish TV director, and it’s pretty straightforward storytelling: this, then this, then this. He juggles (well enough, if unremarkably) three separate storylines, and he presents (well enough, if unremarkably) all that dusty backstory inevitable in a 40-year-old mystery.

It’s the characters, Blomqvist and Lisbeth, that recommend the movie, because they turn certain thriller conventions on their heads. One knows that a man and a woman solving a crime together, particularly a serial crime, particularly a serial crime against women, should never split up as they get closer to a resolution. It’s just asking for trouble. And it happens here. Except the serial killer (Martin, by the way, the former Hitler Youth with the malt whiskey) doesn’t catch the defenseless Lisbeth; he catches the defenseless Blomqvist, whom he ties up, tortures, and is about to kill. It’s up to Lisbeth to arrive in the nick of time and take a golf club to Martin’s back.

But Martin is allowed to escape, and one expects, anxiously expects, as Lisbeth leans down to free Blomqvist, that Martin will return, because the serial killer always returns. Martin’s been at it for 40 years. Inculcated by his father, Gottfried, who sexually abused women, including his own daughter, Harriet, Martin has kidnapped, tortured, raped and killed dozens of women since 1966. He shows Blomqvist a small cage. “I had one in here while we were upstairs sharing malt whiskey,” he says matter-of-factly. He brags about showing these women some small act of kindness, giving them, say, a drink of water, and seeing in their eyes some small hope that they’ll survive; but he does it only for the thrill of extinguishing that hope.

This is the kind of movie villain that never dies, or takes a long time dying, so one anxiously expects him to come roaring back into the room when Lisbeth’s back is turned. Doesn’t happen. Instead she goes after him. She hops on her motorcycle and chases him down. He’s no longer the hunter; she is. It’s a truly thrilling cinematic moment.

Interestingly, the revelation of Martin and his subsequent death doesn’t solve the case. Martin may have been a serial killer, responsible for the deaths of dozens of women, and he and his father may have raped Harriet back in 1965—causing Harriet to kill her father while fleeing her father (remember: there are no accidental deaths in crime fiction)—but Martin didn't have anything to do with Harriet's disappearance. So what happened to her?

Answer: She’s alive. She escaped her family and its crimes and has been living in Australia all of these years. Blomqvist tracks her down, brings her back, and presents her to Henrik Vanger. And the music wells up as these two sweet people have a sweet, tearful reunion.

Me in the audience: Wait a minute. She just left? Allowing her brother to rape and torture and kill dozens of women? How awful. How awful, too, that the movie doesn’t even acknowledge it.

The book does. Or Lisbeth does:

   During the drive [Blomqvist] told her about Harriet Vanger’s story. [Lisbeth] Salander sat in silence for half an hour before she opened her mouth.
   “Bitch,” she said.
   “Who?”
   “Harriet Fucking Vanger. If she had done something in 1966, Martin Vanger couldn’t have kept killing and raping for thirty-seven years.”

In the end “Dragon Tattoo” is a fairly conventional movie that saves itself with its unconventionality. We start out caring about the conventional girl, Harriet, with her long blonde hair and secret smile, who plays the victim, and finish caring about the unconventional girl, Lisbeth, with her chopped black hair, tattoos and nose rings, who refuses to play the victim. We want to protect her—this girl who doesn’t need our protection.