The Tomorrow War starring Chris Pratt is now streaming on Amazon Prime Video and it’s a very silly, very fun ’90s-style blockbuster. It’s an action/adventure story about time travel, killer aliens from outer space, and familial relationships. You know, the usual.

It also has a curveball of an ending! What inspired director Chris McKay and writer Zach Dean to take The Tomorrow War in such a surprising direction? We asked them and found out. And be warned — major spoilers for the film follow.

The Tomorrow War Teaser Trailer

The Tomorrow War Ending Explained

Just when you think The Tomorrow War is over — it isn’t! Dan (Pratt) gets the magical serum from his future adult daughter (Yvonne Strahovski) and brings it back to the past to kill the White Spike aliens before they can take over the planet.

We get a memorable scene of thousands of White Spikes massing together to get to Dan before he warps back in time. The scale is epic, and climatic…and then we’re back in (almost) our time, with a dazed Dan holding the alien-killing venom and 40 minutes left in the movie.

Dan then recruits a ragtag group, including fellow future fighters Charlie (Sam Richardson) and Dorian (Edwin Hodge), as well as his super-buff dad, James (J.K. Simmons). The actual end of the movie follows the group heading to frozen Russia to kill off the original hibernating White Spikes before they wake up and multiply, and the real climatic ending has Simmons and Pratt fighting a single White Spike together.

That shift was very deliberate. Speaking with /Film, McKay shared his thoughts behind the change in scale and the ultimate ending. “These people that we meet in the beginning of the movie, I wanted them to come back,” McKay explained. “Charlie in the original version of the movie dies. Dorian dies in the original version of the movie earlier. I wanted all those people to come back in a meaningful way.”

Just a Father-Son Hunting Trip, With the World at Stake

And come back they did. McKay described The Tomorrow War as starting off as a horror and war movie and then turning into a “man on a mission” movie.

“It just becomes this father and son going on a hunting trip together to take out the last bad guy,” McKay says. “In the end, Chris goes up against it, one-on-one, which to me is just a really great winnowing down of things from a patience perspective. You saw the biggest stuff in the world, you saw millions of [White Spikes], and explosions and stuff like that. So I wanted to have something that felt different and felt a little more fun.”

In the End, the Real Monster is Climate Change

Another big twist revealed during the final stretch of the film is that the alien White Spikes were here all along! Trapped in ice, that is. And with climate change causing land frozen for millions of years to thaw, those aliens got out.

Screenwriter Zach Dean came up with the idea on a family trip to Iceland. He told /Film:

“We were in this boat and there’s an iceberg’s literally floating around. The guide reaches in the water and he grabs this little piece of floating ice with his ice hook and he hands it to my son…and he said, ‘Hey, you want to taste something that’s a million years old?’ And I was like, ‘Oh my God, that’s amazing, right?’” So he tastes the ice and I’m tweaked and I go to the guy and I’m like, ‘So, how long has this lagoon been here?’ I think he’s going to tell me thousands of years. And he goes, ‘This began melting 87 years ago and it’ll be gone in 40.’ And I was like, “Oh my God.” And for a minute I looked at my kids and my wife was pregnant, and I was like, ‘I’m literally looking at the demise of my children,’ as my son’s eating this million-year-old ice.”

Dean took that revelation and made it the focus of the movie’s more personal third act. “It’s a de-escalation of scale, but an escalation of personal stakes,” he explained. “Just when you thought, ‘Okay, I’m maybe getting a little tired [of giant] fights,’ the story shifts and suddenly it’s more personal. Just on a pure storytelling approach, it’s the right kind of jolt that movie needs at that point, right?”

That seems about right. You can catch The Tomorrow War — White Spikes and metaphors alike — on Amazon Prime Video right now.

The post ‘The Tomorrow War’ Ending Explained: The Filmmakers Break Down That Wild Final Act appeared first on /Film.