It’s difficult to pinpoint where exactly Anna Karenina went wrong, because nearly everything about the movie is perfect. Director Joe Wright has an unusually strong track record when it comes to highbrow literary adaptations (he also did Pride and Prejudice and Atonement), and in many ways, Anna is his best film yet. And yet for some reason, it’s almost impossible to sit through the movie without wondering whether or not someone at the concession stand slipped an Ambien in your drink.

Technically, the movie is a marvel to behold. All of the scenes that take place indoors are shot in a highly theatrical, artificial fashion recalling Powell and Pressburger’s classic Red Shoes and Tales of Hoffmann, and the way Wright’s roving camera transitions from one set to the next is stunningly innovative. As expected from such a distinguished cast—which includes Keira Knightley as Anna, Jude Law as Karenin, and Aaron Johnson as Vronsky—the acting is phenomenal. (Knightley in particular has never been better). The score is also first-rate, as are the costumes, production design, cinematography, editing, etc.

So why is Anna such a crashing bore?

The problem, I suspect, resides in Tom Stoppard’s adaptation of Tolstoy’s novel. Regarded by many as the best novel ever written, Tolstoy’s novel actually tells two parallel stories: the story of Anna, who leaves her husband to be with a cavalry officer, and the story of Levin, a Tolstoy-esque landowner and agricultural reformer. It’s the first story for which the novel is famous, and it’s the first story that Stoppard has chosen to adapt.

Why so many people find the adultery plot so fascinating is beyond me. Anna’s story is basically just a glorified re-write of Madame Bovary, and I think it’s safe to say that Tolstoy does not improve on Flaubert. Levin’s story, on the other hand, is actually fairly interesting. Had Stoppard granted Levin more than 15 minutes of screen time, the movie may have been fairly interesting too. Instead, Stoppard focuses almost exclusively on Anna’s affair, and tediously drags it out step by agonizing step.

And there are a lot of steps: first Anna meets Vronsky at a ball and the two seem to instantly fall in love, then an infatuated Vronsky follows Anna to St. Petersberg where their relationship intensifies, then Anna’s husband Karenin begins to get suspicious and confronts Anna but she denies everything, then Vronsky participates in a horse race and Anna overreacts when he crashes, prompting Karenin to confront her again, at which point Anna confesses everything, then Anna asks for a divorce but Karenin refuses, then Anna becomes pregnant with Vronsky’s child, then Karenin finally agrees to a divorce, then Vronsky and Anna go to Italy and when they get back Anna is shunned by society, and…why doesn’t she just jump in front of the train already?

The first major Hollywood adaptation of Anna Karenina (the 1935 version starring Greta Garbo) also focused exclusively on Anna’s story. It was 95 minutes long. This version is apparently 129 minutes long. It feels more like 219.