400 Days

400 Days

Year: 2016

Runtime: 91 min

Language: English

Director: Matt Osterman

Sci-FiMysteryThriller

A team of four astronauts undertakes a rigorous, year-long simulation preparing them for a journey to a distant planet. As the isolation deepens and contact with Earth diminishes, the psychological pressure mounts, threatening their mental stability. When communication abruptly ceases, the crew begins to doubt the mission’s true purpose, suspecting a hidden agenda and questioning the nature of their reality.

Warning: spoilers below!

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400 Days (2016) – Full Plot Summary & Ending Explained

Read the complete plot breakdown of 400 Days (2016), including all key story events, major twists, and the ending explained in detail. Discover what really happened—and what it all means.

Four astronauts—Captain Theo Cooper, Dr. Emily McTier, Bug Kieslowski, and Cole Dvorak—embark on an ambitious journey to undergo a 400-day-long simulation on Earth designed to analyze the long-term effects of space travel. As they spend their time in isolation underground, the crew faces increasingly severe psychological challenges, including paranoia and hallucinations. As tension grows, each member begins to retreat into their own space, both physically and mentally.

One fateful day, a disheveled man unexpectedly appears in their simulated spacecraft, breaking through the boundaries of their isolation. After his sudden departure, the astronauts make the bold decision to exit their underground haven and explore the outside world, only to discover a landscape that has drastically changed. They find the Earth to be enveloped in darkness, with howling winds and an eerie sense of desolation as dust clouds shroud everything in an oppressive gloom.

Venturing forth, they stumble upon a town called “Tranquillity,” which surprisingly boasts inhabitants and electricity. A local man named Zell invites the weary travelers into his diner, where he explains that the moon was hit by a colossal object that unleashed a massive dust cloud, now blocking out sunlight and drastically altering their environment. Despite this alarming revelation, Dvorak remains skeptical, convinced that they are still caught in the simulation, and chooses to venture off to a nearby bar, a decision soon followed by his comrades.

After indulging in a few drinks, Dvorak leaves with a young woman, opting to disregard the safety of his crew. The remaining trio returns to the diner, where Zell extends an invitation for them to rest the night. Bug, taking the first watch, soon finds himself lost in hallucinations, believing he is following his son, Sam, yet unwittingly challenges Zell in the process. When McTier and Cooper awake, they are alarmed to discover that their friends have vanished. When they question Zell about the missing crew members, he curiously claims that they arrived alone, raising suspicion and alarm in McTier and Cooper.

Fearful for their well-being, the duo sets out to find their comrades but is unable to locate them. After a frantic search, they return to their ship, only to realize that they are being trailed by Zell and two other sinister men. A tense confrontation ensues, culminating in Cooper and McTier successfully neutralizing the threats. In a twist of fate, the moment Zell takes his last breath coincides with the conclusion of the 400-day simulation, which the astronauts receive notification has ended successfully.

As the entrance hatch opens, they are greeted by a blinding light, prompting Cooper and McTier to grasp each other’s hands tightly, their hearts racing with anticipation of what lies ahead. The film closes on this moment of uncertainty, leaving audiences on the edge of their seats, wondering about the fate that awaits them beyond the simulation’s end.

Last Updated: May 12, 2025 at 07:04

Ending Explained – What Happens at the End of 400 Days?

Still wondering what the ending of 400 Days (2016) really means? Here’s a spoiler-heavy breakdown of the final scene, major twists, and the deeper themes that shape the film’s conclusion.

At the end of 400 Days, the story leaves viewers uncertain about what was real and what was simulation. The crew’s entire experience—marked by hallucinations, secrets, and mysterious occurrences—could have been either a realistic trial or a carefully constructed illusion. When they step outside into a seemingly post-apocalyptic world and meet Zell, it raises questions about whether the catastrophe aboveground truly happened, or if it was part of the simulation. The movie deliberately keeps these truths ambiguous, emphasizing that some mysteries in life are beyond understanding. This open-ended conclusion invites the audience to interpret whether their ordeal was a tragic real event or a complex psychological test.

As for the mission’s purpose, the film offers no definitive answer. Its stated goal sounds simple—exploring space and human resilience—but the crew’s flawed characters cast doubt on whether they were truly qualified or if the mission’s purpose was something hidden and more sinister. Characters like Theo, who shows irresponsibility, and others with secrets or mental strain, imply that the real reason for the mission might have been concealed from them all along. This adds to the overarching theme of distrust, where no one can be fully relied upon, not even among the crew or scientists overseeing them.

Director Matt Osterman has acknowledged that he prefers to leave the ending open to interpretation. He hints that the true emotional core is about the relationship between Theo and Emily, which he describes as a focal point of the story—highlighting that sometimes, what matters most in a confusing narrative is human connection rather than certainty. Ultimately, the ending challenges viewers to accept uncertainty and reflect on how humanity’s obsession with knowledge can sometimes lead to moral and ethical pitfalls. In the end, 400 Days reminds us that some questions about truth and trust may remain forever out of reach, and that’s perhaps the most profound message of all.

Last Updated: June 25, 2025 at 09:00

Unlock the Full Story of 400 Days

Don't stop at just watching — explore 400 Days in full detail. From the complete plot summary and scene-by-scene timeline to character breakdowns, thematic analysis, and a deep dive into the ending — every page helps you truly understand what 400 Days is all about. Plus, discover what's next after the movie.

400 Days Timeline

Track the full timeline of 400 Days with every major event arranged chronologically. Perfect for decoding non-linear storytelling, flashbacks, or parallel narratives with a clear scene-by-scene breakdown.

400 Days Timeline

Characters, Settings & Themes in 400 Days

Discover the characters, locations, and core themes that shape 400 Days. Get insights into symbolic elements, setting significance, and deeper narrative meaning — ideal for thematic analysis and movie breakdowns.

Characters, Settings & Themes in 400 Days

400 Days Ending Explained

What really happened at the end of 400 Days? This detailed ending explained page breaks down final scenes, hidden clues, and alternate interpretations with expert analysis and viewer theories.

400 Days Ending Explained

More About 400 Days

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More About 400 Days

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