The first season of Invasion on Apple TV Plus feels a little incomplete. Across its 10 episodes, which chart a handful of humans grappling with an alien invasion, the story slowly teases out the reality of what’s happening. There are hints here and there — a haunting artificial voice, a mysterious alien-killing weapon, a kid with seizures that may or may not show the future — but the biggest reveal of all doesn’t even happen until the very last shot in the final episode. It still managed to pull me in — but that pull has a lot to do with potential. Rather than standing on its own, the initial season of Invasion feels like the first chapter of a much grander science fiction epic.

Invasion gets off to a slow start. Unlike most stories about an alien invasion, which tend to focus on the alien part, Invasion lingers on human trauma. Early on, there’s barely even a mention of the invading extraterrestrials. Instead, Invasion’s global story tracks a handful of different threads spread across the world, which ultimately end up loosely connected. Each has some tie to the otherworldly events: there’s a young boy in London who is prone to seizures that may be connected to the invasion; a family from Long Island that’s struggling with infidelity and also happens to possibly have a weapon that can kill the aliens; a space engineer in Japan who seems to be the only one able to communicate with them; and an American soldier who is separated from his squad in Afghanistan after what appears to be an attack.

The show does a great job of making you care about these characters, mostly because you spend so much time with them. You understand why the engineer is working tirelessly to find a stranded astronaut after lots of long, heartfelt scenes revealing their secret relationship. Likewise, while the soldier comes across as a jerk initially, his slowly revealed backstory ultimately turns him into a sympathetic figure. There’s lots of great character development going on, but it also requires patience since it takes quite a while to get to the actual aliens. For the first half of the season, it’s mostly just hints that there’s something going on beyond a natural disaster of some kind.

This all means that when the aliens do finally appear, it’s a huge deal. The reveal is great and neatly changes the tone of the show. From then on, Invasion becomes something different, balancing out its character drama (which never fully goes away, thankfully) with some intriguing alien mysteries and the flat-out horror of dealing with the invaders. There’s a terrifying scene in a secluded house, where a family tries to sneak away from one of the spiked blob creatures; later, we see the soldier making his way through a war-torn hospital amidst an infestation as if this was a first-person Resident Evil game.

What you don’t get are much in the way of answers. There are some small revelations, like when you learn that the London teen had visions of the invasion before it happened or when it appears that the Japanese researcher discovers how the aliens communicate. But nothing is ever clear. Even when it seems like the aliens have been defeated, the show throws another twist at you. This isn’t necessarily a bad thing. Mystery is important, and those unknowns are part of what has kept me coming back. But the result is that season 1 doesn’t feel like a complete story, with its own distinct arc. It’s 10 episodes of setup.

The good news is that Apple revealed earlier this week that Invasion is coming back for a second season, with co-creator Simon Kinberg saying they would be “expanding our universe in the most intimate and epic ways.” And after a full season of setting things up, I’m anxious to see where it’s finally going.