The Silent Sea Ending Explained

The Silent Sea races to a soggy conclusion as it answers the many questions at the heart of its lunar mystery.

Bae Doona as Dr. Song in Netflix's The Silent Sea
Song Jian Photo: Netflix

This The Silent Sea article contains MAJOR spoilers for the Netflix k-drama.

Netflix got in one more grim K-drama before Christmas: moon mystery The Silent Sea. Because nothing says Christmas like a spooky, abandoned lunar base! The drama stars Bae Doona (Cloud Atlas, Kingdom) as Dr. Song, an astrobiologist-turned-ethologist who agrees to go on a mission to the lunar base where her sister died in order to retrieve a mysterious “sample.”

The story is set in a probably-too-near future in which climate change has rapidly reduced the Earth’s water supply, leaving the surviving population to fight for the unevenly distributed resource. Song is part of a team that includes a doctor, two pilots, some engineers, and several seemingly experienced astronauts, including Captain Han, played by Gong Yoo (Train to Busan, Squid Game). While Captain Han is in charge of the mission, Dr. Song has control over any decisions having to do with the unstable and very dangerous “sample.”

What Happened on Balhae Station?

Balhae Station was a lunar research base led by Dr. Song’s sister, as part of a project undertaken by the National Ministry of Defense. As Dr. Song eventually learns, the scientists at Balhae Station were tasked with finding a way to make lunar water safe and plentiful for the human population. At some point, Director Choi decides that the project is too much of a PR nightmare should the secrets of the child experimentation gets out, and has the base shut down and everyone who works there left to die via exposure to the lunar water. She doesn’t believe there will be any survivors, but she is wrong…

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Why Are People Turning Into Water?

I’m glad you asked. When lunar water is exposed to the human body, it multiplies exponentially inside of the host until they are dead, drowned from the inside out. Lunar water is a hopeful discovery in the sense that it could solve Earth’s water scarcity problem, but bad in the sense that lunar water, you know, usually kills its host.

It’s terrifying to imagine how lunar water could be abused in the wrong hands. As evidenced by the fight for water regulation abolition on Silent Sea‘s Earth—and you know how inequality and capitalism works on our Earth—it’s not hard to imagine immoral businesspeople killing people in exchange for the lunar water they produce. Of course, lunar water is useless unless people can consume it. Otherwise, humans are viral drowning in a dry, thirsty world.

Who is Luna?

Luna, or more specifically Luna 073, is the only clone who has survived the experimentation process. Unlike her 72 predecessors (yes, the Balhae team killed 72 kids before getting it right), Luna is not only able to survive exposure to the lunar water, but is changed by it. She becomes super fast and strong, is able to heal her own wounds when exposed to lunar water, and her body produces antibodies that can make other humans able to consume lunar water themselves. (Dr. Song is able to survive exposure to lunar water after sustaining a bite from Luna.)

As Dr. Song and Captain Han eventually agree upon, Luna is the potential savior of Earth. But what might that look like? SAA Chief Kim (Squid Game‘s Heo Sungtae) admits to them that, while he has grown unsettled by Director Choi’s unchecked power, he is fine with an outcome that would see Luna living out the rest of her probably numbered days being experimented on at a Ministry of National Defense facility. Dr. Song comes up with an alternate plan: bring Luna and the lunar water samples to The International Institute of Space Biology, which seems somewhat akin to our ISS. Dr. Song sees the institute as a more neutral area to continue to research the possibilities of lunar water outside of one government or corporations sole control.

What Happened to Dr. Song’s Sister?

Not only did Dr. Song’s sister work on Balhae Station, she was the chief researcher. This means that she led the research project that involved experimenting on children, leading to dozens of brutal deaths. Before Song’s sister dies, she sends Jian a message: FIND LUNA. It’s what drives our Dr. Song to agree to the mission, as she wants to understand why her older sister was there and how she died. While Song doesn’t actually get to talk to her deceased sister, she imagines the conversation, using the logs she has found that paint a better picture of other Dr. Song’s path. “Jian, I wanted to show you the sea,” she says. As for what Sister Song wanted our Dr. Song to do once she found Luna, it’s unclear. All that is clear is what Dr. Song decides: she will treat Luna like the thinking, feeling human that she is.

The personal connection is also what convinces Director Choi to bring Dr. Song on for the mission—or at least that’s what Jian theorizes. Choi believes that Dr. Song will not reveal the truth of what happened at Balhae Station because she wouldn’t want the public to know the atrocities her sister committed there.

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What is RX?

In the final episode, it is confirmed that both Lieutenant Ryu and co-pilot Lee Gisu were hired by RX, which is described in Episode 2 as “a transnational corporation. RX is short for Resource Exploration for Space Mining and Planetary Development. They sound like a corporate-funded group of space mercenaries who work to secure resources that can then be sold to the highest bidder, and they are pretty much sabotaging the mission from the beginning.

Why Did Lieutenant Ryu Work for RX?

While Lee Gisu seemed both mentally unwell and also in it for the money, Lieutenant Ryu had a much more personal reason for working for RX: he was a member of the Ministry of National Defense mission to close Balhae Station—”close” being a euphemism here for “sabotage and leave hundreds of people to die.” Consumed by guilt and angry at the governmental higher-ups for their role in the massacre, he more or less decided to start working for their enemy. When he is dying from lunar water exposure in “The Silent Sea,” he keeps apologizing to Dr. Song. It’s because he remembers closing and locking the base doors that would condemn her to death.

Why Does Captain Han Stay Behind?

In the final act of “The Silent Sea,” Captain Han realizes that they won’t be able to activate the decompression chamber from inside the chamber (because of course), and that someone must stay behind to do it. Without telling Dr. Song or Doc Hong (Crash Landing On You‘s Kim Sun Young), he returns to the prior chamber and activates the depressurization process for them, ensuring that the doctors and Luna will be able to safely leave the base.

Does Captain Han Die?

Poor Captain Gong Yoo. Though it initially seems like Han dies in the effort, as the chamber he is in floods with lunar water, when the water eventually bursts out of the base and into the lunar atmosphere, he is thrown with it. Luna finds him, offering him back his badge with his daughter’s sticker on it. He doesn’t take it, but is given the chance to see that Luna has survived and is roaming freely on the lunar surface without a spacesuit. Before he dies, he is able to see that he completed his mission, as it would come to be defined by himself and Dr. Song: save Luna and the sample, ensuring hope for Earth.

Who Survives and Who Dies in The Silent Sea?

Honestly, so few people survive. (R.I.P., Mr. Hwang, who doesn’t even make it to the base.) In the end, of the 11 people who started the mission, only two people make it: Doc Hong and Dr. Song. Luna also survives, though she wasn’t part of the initial mission. Interestingly, everyone who dies is a man and every one who survives is a girl or woman.

Will There Be a Season 2 of The Silent Sea?

As with most series on Netflix, a second season will mostly likely be based on how well the first season does. I doubt The Silent Sea is going to get Squid Game or even Hellbound numbers—it’s a big too sluggish in its pacing—but that still leaves plenty of room for success. That being said, like most K-dramas, The Silent Sea does tell a complete story. While there are questions left to be answered—most urgently, what will become of Luna?—this show, based on a short film by director Choi Hangyong, tells a relatively short-term, confined story that answers the big questions poised at its beginning.

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