Netflix's Stowaway ending explained: Why [spoiler] died and your top questions answered

Now Netflix’s Stowaway steps up with a compelling psychological drama, following a three-person team starting their two-year mission to Mars in an attempt to build a colony.

It starts out hopeful, as the crew of the Kingfisher get comfortable for the long haul, joking with each other and establishing a friendly working dynamic. Medical researcher Zoe Levenson (Anna Kendrick) banters with biologist David Kim (Daniel Dae Kim), while the steely Commander Marina Barnett (Toni Collette) leads the trio. Their craft/research station is tied via lengthy cables to the main hull of the Kingfisher, as the huge contraption spins to create a form of artificial gravity, allowing the crew to live fairly normally day-to-day.

Unfortunately, their journey is thrown into jeopardy when they discover a member of the ground crew, Michael Adams (Shamier Anderson), is still on board. His presence ruins the meticulously planned mission as resources start to diminish. They’re all faced with truly impossible decisions, as they scramble to stay in control of the situation.

Warning: major spoilers for Stowaway will be discussed from hereon out.

How did Michael get on the ship in Stowaway?

It’s not until around 18 minutes into the Netflix Original that Michael’s presence is discovered by Marina, when she spots blood dripping from the ceiling. His harness had snagged on some of the wiring before the unconscious engineer comes crashing down into the main craft. Eventually, Michael wakes up in the understandable panic that anyone would find themselves in if they’d accidentally been brought along on a two-year long mission to Mars.

After Zoe manages to calm him down, Michael explains that he was tasked with arming the second-stage firing pins, a job he clearly completed otherwise the Kingfisher would never have taken off. But he wasn’t buckled into his safety harness properly, which meant he fell sometime before take-off and was knocked unconscious.

Clearly, someone was cutting corners during the final flight checks, because Michael wasn’t discovered until 12 hours into the journey. Unfortunately for him it’s too late for them to head back home, even though he's panicking about leaving his little sister unattended, adding some extra emotional stakes into an already incredibly tense situation.

There’s a brief moment of paranoia in Stowaway about Michael, with Marina asking the rest of the ground team if there’s any possibility the engineer snuck aboard purposefully to try to sabotage the mission. The Commander even debates restraining him, before eventually settling down and realising that Michael himself isn’t knowingly trying to cause trouble. Don’t expect a third-act twist where he’s revealed to be an extraterrestrial threat, or a murderous serial killer, à la Sunshine. This is a story about resilience in the face of defeat, not an epic science-fiction adventure.

What happens in Stowaway?

Michael’s presence onboard isn’t necessarily an issue, until the crew realises that he accidentally damaged a vital piece of equipment during take-off while he was unconscious. The CDRA device, which scrubs out Carbon Dioxide from the atmosphere in the ship, is completely destroyed. They find a number of half-measures to survive as long as they can, like using their emergency canisters of lithium hydroxide to do the CDRA’s job, but this only leaves enough oxygen for two crew members to make it to Mars, not four.

Even when they create more oxygen with the algae David was cultivating for the Martian colony, there’s only enough to sustain three crew members. This is where the impossible decisions start creeping in. If they have to pick one person to die, who should it be?

Commander Barnett is in charge of the ship, she’s vital in flying the craft and landing on Mars, so it can’t be her. The film establishes early on that David has a wife back home, giving him the extra emotional motivation for staying alive. And Zoe is Kingfisher’s doctor, she needs to be on hand if anyone gets hurt.

It simply has to be Michael… Or does it?

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Stowaway ending explained: Why did Zoe die?

In a last ditch attempt at getting enough oxygen for all four crew members, Zoe and David decide to climb the cables up to the Kingfisher’s main hull, where there are tanks of liquid oxygen. It’s an arduous climb, as they’re fighting the forces of gravity on the way up. And although they manage to retrieve one tank, the film throws yet another curveball at the struggling crew - there’s a solar flare on its way, which will kill Zoe and David with radiation if they don’t get back in time.

Zoe’s descent back to the craft is a little quicker than she anticipated, as she can’t grip onto the cable properly. And when she finally reaches the bottom, she drops the canister of that all-important liquid oxygen into the vastness of space. It’s a devastating moment, watching it spin away into the cosmos. But after a brief moment of contemplation, Zoe chooses to ascend up the cable again to retrieve the last canister, sacrificing herself so the remaining trio can make it to Mars. Anna Kendrick’s character quickly succeeds in getting the remaining tank, but obviously pays with her life.

The ending of Stowaway is a relatively quiet affair, choosing to focus on Zoe’s words from earlier on in the film, where she explains the mission would “truly give my life meaning beyond anything I could imagine”. It’s a peaceful end for Zoe, who sits on top of the ship looking at Mars while she’s surrounded by a swirling array of colourful radiation, slowly dying as Volker Bertelmann’s score reaches an emotional crescendo.

Since we never once get a peek into Zoe’s personal life, aside from the fact that she went to Yale University, it makes sense why she was the one who felt she could do what was necessary to save the team. Her caring and compassionate nature as a doctor revolves around helping others rather than herself, bringing the story to a close. Since Stowaway ends on a shot of Mars in the distance, it’s left to the audience to imagine that the surviving crew members made it there alive.

Stowaway is streaming on Netflix now. Want something else to watch? Check out our Sci-Fi page or our full TV Guide.