Publisher Square Enix and developer Eidos-Montreal revealed that Lara Croft will have a showdown with the Mayan apocalypse in the upcoming Shadow of the Tomb Raider. The final game in the rebooted Tomb Raider trilogy will be out on September 14 for PC, Xbox One, and PlayStation 4.

Shadow of the Tomb Raider’s new trailer is gritty and beautiful, set in the dense jungles of Latin America. It’s a lush background to blood-splattered scenes of human sacrifice. According to Eidos narrative director Jason Dozois, Lara will have to make a hefty decision at some point in this game, and it’s one that could either save the world from the brink of destruction or damn it.

At a press event on Thursday, our hands-on demo started in Mexico, where the secretive Trinity organization has been excavating a temple. They’re after a ceremonial dagger, but of course Lara gets there first — and when she grabs it, she sets into motion the events that will allegedly lead to the end-times. An ancient Mayan prophecy promises the Earth will suffer devastation from earthquakes, tsunamis, and volcanic eruptions. But if someone can use the dagger with another artifact, referred to only as “the silver box,” they’ll have the power to reshape the world instead.

That’s what Trinity’s after — and, as head honcho Dominguez tells Lara, using the two artifacts to do this might be the only way to stop the apocalypse.

In a presentation, Dozois explained how Lara’s character and her environment have evolved over the course of the series. As she becomes more confident and lethal, so does the landscape — Shadow of the Tomb Raider promises creepier, deadlier underground tombs and even harsher conditions for survival, such as the threat of parasites and poison in the jungle.

The demo was action-packed, showing off the grim tombs that Lara will excavate in the full game. Sharp spring-loaded spears pop out at her and she must scramble away. Sometimes she has to head underwater to explore further, which leads to claustrophobic sequences with the ever-present danger of drowning. These scenes in particular had excellent sound design, evoking panic while Lara struggles to squirm up a crevice so that she can breathe.

In this game, Lara will complete her transformation into what Dozois calls “the ultimate apex predator,” but she will also see the consequences of her previous decisions. The fact that she’s responsible for the impending apocalypse perhaps teases the possibility of a team-up with her archenemies Trinity — though more likely, she will have to do some soul-searching about the single-minded way she approaches her mission.

At the end of the demo, Lara wants to go after Trinity but her friend Jonah Maiava insists that they first stay behind and help the Mexican town they’re in. It’s been wrecked by a flood that’s killed many and left many more injured. He shouts at her for her selfish instinct to chase after her nemesis instead.

The way Lara pursues her vendetta against Trinity and the consequences of her actions are at the core of Shadow of the Tomb Raider. Dozois says that the game is in part about Lara learning that “tomb-raiding in the wrong context can be destructive,” such as when she picks up the dagger without thinking. Other people have to suffer the onslaught of impending doom, and it came about because of her impulsiveness.

“Coming from someone who’s very reactive in Tomb Raider 2013, she’s put in a horrible situation, has to survive,” said Dozois in an interview, describing how Lara has progressed as a character over the series. “When you get into [Rise of the Tomb Raider], it’s her going out and proactively searching for stuff, and then coming into conflict with groups like Trinity. And now, going too far, overstepping her bounds, being so obsessed with trying to take them down and not realizing the impact her own actions are having on herself and the world.”

“That thought also plays into the gameplay as well,” said Eidos-Montreal lead game designer Heath Smith. “We have a theme called ‘one with the jungle.’ The jungle is the new setting, it’s the most dangerous place on Earth, everything is trying to kill you. And so in this setting, she has to use the tactics of fear, she has to use mud to camouflage herself, when you do that, if you really went and did that, you could go over the edge. When you go down that rabbit hole, you have to make sure you don’t go too far that you can’t come back.”

In Shadow of the Tomb Raider, Lara will interact with a whole hidden city of people, giving her new perspectives and personalities to bounce off of in her quest to stop Trinity. As she chases the “silver box” into the jungles of Peru, allies like Jonah will question her tunnel vision and suggest that maybe she’s become too consumed by her mission. These relationships are ways for her to explore the dark places her obsession is taking her. And the new mechanics also reflect this as well, such as rappelling down walls and underwater exploration.

“At Eidos-Montreal, what we try to do is keep up the narrative theme of Lara’s kind of descending into slight darkness, a slight sort of unstable mental state here, so we try to introduce all the new traversal based on that,” said Smith. “So you’re descending by the rappel and the wall run, you’re descending underwater into the new spaces which are not just — while there is exploration and discovery, it’s also claustrophobic and fearful.”

Which comes back to that important decision that Dozois teased during the Shadow of the Tomb Raider presentation. Will Lara choose to stay in the darkness, or will she muster the will to climb back out? The game looks like it will tackle that question at full speed, taking on both her internal and external conflicts with high-velocity action in a gorgeous new setting.