Pokémon Go, explained in fewer than 400 words

If you’ve been on the internet — or, um, outside — lately, you may have noticed that a game called Pokémon Go is suddenly taking the world by storm. It may have you wondering, especially if you were born before 1984, just what the hell is going on.

Pokémon is a Nintendo franchise that launched in the 1990s. In its world, “trainers” travel the world to catch varied monsters called Pokémon — rats, dragons, swordlike creatures, and more — and use these critters to fight each other. The trainer’s goal is to “catch ’em all,” as the franchise’s slogan suggests, and become a Pokémon master by defeating prestigious trainers known as gym leaders and Elite Four.

So what is Pokémon Go? Unlike previous Pokémon games, it’s not for Nintendo’s handheld consoles; it’s a free download for Android and iOS devices. It also doesn’t play at all like previous Pokémon games: Although the goal is still to catch ’em all, Pokémon Go is an augmented reality game — it mixes real-world elements with the game.

The big thing is Pokémon Go uses your phone’s GPS and clock to decide which Pokémon appear in the game. If you’re at the park, more bug and grass types appear. If you’re by a lake, more water types appear. If it’s night, more nocturnal ghost and fairy types do. So Pokémon won’t just come to you; players have to traverse the real world to catch ’em all.

Pokémon Go also has gyms — where you can fight gym leaders — and PokéStops based on real-world locations, which create hubs where players can meet. (You can buy, with real money, items to lure Pokémon to these stops; that’s how Niantic, the game’s developer, makes money.)

So why is the game taking off now? Well, it just came out, so it’s new and exciting. But it’s also free, making it easy to pick up. And it taps into nostalgia for those who played Pokémon in the ’90s. Specifically, Pokémon Go realizes a vision Pokémon fans have had since the series came out: What if Pokémon were real, and inhabited our world?

It’s also exciting because it’s the first big augmented reality game. Although others (like Ingress and Life Is Crime) tried before, none reached the heights of Pokémon Go. But with Pokémon Go’s success, it’s something you can expect more of in the future.

To read more about Pokémon Go, check out Vox’s full explainer.