The first act of Charlie Kaufman and Duke Johnson’s animated film Anomalisa plays out as an unassuming, slice-of-life drama: It follows an Englishman named Michael Stone (David Thewlis) as he flies to Cincinnati, takes a cab to his hotel, and checks into his room, brusquely interacting with chatty strangers the whole time. But the film—made with stop-motion animation and eerily realistic, 3D-printed puppets—is slowly pervaded by a sense of horror. As Michael chats with his cab driver about Cincinnati chili, or a hotel clerk about the kind of room he wants, it becomes clear that every other character, whether male or female, is speaking with the same voice (Tom Noonan’s, to be precise). It’s a remarkably effective depiction of the world’s sameness, seen through the eyes of a character who’s long forgotten how to connect with people.

Into this nightmare walks—what else—a special woman. Anomalisa, like so much of Kaufman’s work, is about someone who sees himself as existing outside of society, and who’s both emboldened and depressed by that fact. If that sounds like a tough person to spend 90 minutes with, well, it is. He’s a man who sleepwalks through life, who’s fallen for and walked away from multiple women for reasons he can’t explain, who literally sees everyone else as a drone. That is, until he hears Lisa (Jennifer Jason Leigh), another hotel guest, whose voice stands out of the crowd for him. As Anomalisa explores their meet-cute, watching the movie evolves into a frustrating internal struggle: Should viewers feel happy for the pair? Or terrified for Lisa?

As voiced by Leigh, Lisa is the standout character of the film—which, of course, she’s meant to be. A shy but warm-hearted and appreciably goofy soul, she brightens up a film that’s often near-impossible to watch when it’s focused on the somnambulant Michael. Through the theatrical device of having her voice stand out in the crowd, and the pinpoint casting of Leigh (who’s always excelled at playing alluring weirdos), Kaufman and Johnson find a wonderful new angle on depicting what it’s like to fall hard for someone. The hard part is watching it happen to a man as thoroughly awful as Michael.

To be fair, Anomalisa has genuine sympathy for its protagonist and his flaws; its main challenge is getting viewers to feel the same way. Very early on, viewers learn about Michael’s history of unhappy, short-lived relationships. The minute Lisa draws his attention, the film’s existential horror shifts from the world around Michael to the passion he suddenly feels for Lisa, which he fears will slip away at any moment.

After 40 minutes of aggressive, intentional dullness, Anomalisa becomes far more compelling to watch. Though puppet sex is notoriously difficult to pull off, a scene between Michael and Lisa is astonishing in its awkward intimacy. Though the content itself is pretty gentle, it’s unsettling to watch simply because it feels so realistic and ordinary—one of those romantic sequences where Kaufman and Johnson’s direction really shines. Given the incredible human likeness of the puppets, the uncanny valley should pose a problem, but it doesn’t, which feels like a feat on its own.

Despite its focus on romance, on the whole Anomalisa left me cold, perhaps because of its narrow focus and predictable ending. Yes, Michael is a lonely, perhaps clinically depressed soul whose issues with intimacy could fill a psychiatrist’s pad. But he makes for a surprisingly dead-end protagonist after so many Kaufman scripts that explored identity and life on a much grander scale, from Synecdoche, New York to Being John Malkovich. The impact of Anomalisa’s early drudgery lingers, even after the arrival of Leigh’s character. But Kaufman’s writing works best when it’s about people genuinely contending with what it means to be human. If Anomalisa fails, it’s because Michael can’t quite bring himself to relate to anyone else on earth.