Post-apocalyptic stories, as a rule, are less about the end of the world and more about what it really is to be a human. Is it our capacity to think rationally and logically? Our drive to create civilizations? Our creative power? Our self-destructive streak?

Plenty of post-apocalyptic stories have posited answers like those. But two others show up in Reed Morano’s I Think We’re Alone Now: Our humanity lies in our ability to connect with one another, and in our ability (or perhaps inability) to escape the past. The film handles one of those themes more deftly than the other, but in the end it still adds up to an often moving meditation on what it really means to be human, packaged in one of the oldest post-apocalyptic subgenres: the story of the last man on earth.

The story (from a screenplay by Mike Makowsky) lies somewhere in the intersection of survival tale, relationship drama, and Black Mirror episode. It’s in good hands with Morano, who’s best known for her Emmy-winning work directing the first three episodes of Hulu’s The Handmaid’s Tale, itself a vision of a dystopian future with elements of a relationship drama.

Morano is also a highly respected cinematographer, and she both directed and shot I Think We’re Alone Now. The result is, of course, visually stunning, a movie that makes a nearly post-human world look like a symphony of colors, landscapes, and light.

In the middle of that post-human landscape is Del (Peter Dinklage), whose days are spent alone in a small upstate New York town, following a predictable rhythm. He methodically cleans the houses in the neighborhood: strips the house of useful materials like batteries, drags out the decomposing corpses and buries them in a field, cleans up, and then marks the street outside the house with a huge spray-painted X to signal its completion. He fishes and cooks dinner, reads books from the library, and watches DVDs of classic movies on a laptop, discarding the laptop when the battery dies and picking up a new one from the pile to continue.

It’s not a particularly social existence, but it’s an orderly one, one he seems to have developed over some period of time following an apocalypse. What exactly happened in that apocalypse isn’t clear. It also isn’t really the point of the movie. What’s important is that Del is alone.

Alone, that is, until the arrival of the spunky and auspiciously named Grace (Elle Fanning), whom Del discovers in a crashed car by the side of one of the streets he’s been clearing. She’s alive, and while she’s unconscious, he brings her home and bandages a wound on her head. Then he’d like her to leave. But Grace seems determined to stay. And she’s brought more baggage with her than Del bargained for.

For a while, I Think We’re Alone Now feels like a more serious version of the first season of the sitcom The Last Man on Earth — somewhere between an exploration of what it would be like to be alone in the world and a relationship drama. Grace prods the reluctant Del into teaching her how to clean houses and coaxes him out of his shell — which, it turns out, he assumed before the apocalypse, when he was a lonely librarian living in the town.

It is the slow connection between them that furnishes the film’s strongest argument for what makes us human. Rendered in beautiful landscapes and sensitive detail by Morano, and with two exceptionally strong performances by Dinklage and Fanning, the movie doesn’t so much tell you that they’re growing to care for one another as let you watch it happen.

The idea that our only hope for human survival after the apocalypse is our connection with one another isn’t a new one, of course; everything from The Road and Mad Max: Fury Road to Wall-E and Zombieland posits the same answer. But there’s a reason we continue to come back to it in our storytelling — because it’s true — and I Think We’re Alone Now’s version, like Zombieland, gives us a protagonist who had already experienced a kind of post-apocalyptic loneliness before anything had happened to the rest of the world. Hearing him talk about his life before and his life after, we understand the pain he felt, and it makes the post-apocalyptic salvation in the form of Grace feel even more meaningful.

The other big idea in the film isn’t easy to explain without spoiling it, but it deals with another common theme in post-apocalyptic and dystopian stories: the question of whether, given the choice, it would be better to erase painful memories from our minds, or whether it’s those memories that make us human. This is a central question in a number of Black Mirror episodes as well as movies like Eternal Sunshine of the Spotless Mind: If we were to take away those things from the past that hurt us, would that make us happier humans, or would we become some other kind of beings altogether? This thread feels rushed in I Think We’re Alone Now, and the movie would likely have been improved by a more careful seeding of the idea early on.

In the end, I Think We’re Alone Now isn’t very interested in constructing a mythology or exploring the apocalypse itself. It’s more of a relationship drama, one that works as a showcase for two great performances against a post-apocalyptic backdrop that ups the stakes; after all, if you’re the last people on earth, you can’t just go talk to someone else. So if the movie feels rushed in its second half, its pieces still add up to a beautifully humanist whole: Whether the world is worth preserving depends on whom you decide to preserve it with.

I Think We’re Alone Now premiered at the Sundance Film Festival and opens in theaters on September 21.