The Ending Of Netflix's The Silent Sea Explained

After releasing it on December 24, 2021, Netflix has a new hit sci-fi series in the South Korean show "The Silent Sea." Set in a dystopian future in which water is a scarce resource on Earth, the series features a world searching for hope and answers on other planets, and having no luck. The show stars Gong Yoo ("Train to Busan," "Guardian: The Lonely and Great God") as Captain Han Yun-jae, a literal man on a mission put in charge of a crew sent to the deserted Balhae Station on the moon, where everyone supposedly died five years earlier of radiation, in order to retrieve a valuable sample. 

One of the key members of the crew is astrobiologist Dr. Song Ji-an, played by Bae Doona ("Sense8," "Kingdom"), whose older sister, Dr. Song Won-kyung (Kang Mal-geum), died in the tragic event at Balhae Station, though she keeps this a secret from the others. She wants to know the truth of what happened to Won-kyung, but she also received a strange message from her sister before her death telling her to "Find Luna," which drives her to travel to Balhae. 

Along with a few other team members, they all embark to Balhae Station on the moon for this mysterious sample. But the mission is anything but easy, as everyone's true agendas come out and even more dangers reveal themselves in the station. With eight episodes total in Season 1, "The Silent Sea" is a tense mystery drama with a thrilling end to the season, but what exactly does it all mean?

So what really happens in the final moments of the first season? The final episode of "The Silent Sea" ends with a rescue ship arriving with the intent of heading back to Earth, but not much else is known for certain, including the status of Song, Dr. Hong Ga-young (Kim Sun-young), and Luna's (Kim Si-a) health and overall state. Everyone else from the mission dies in one way or another, with the two doctors and the child being the only survivors. Even Han, who seems so close to surviving, sacrifices himself in the final moments so that the others can escape with Luna.

As for the lunar water, they have some samples, but there's no way anyone else can get more, as Balhae Station is completely destroyed by the water itself. This gets rid of one problem for Song, as it means the Resource Exploration for Space Mining and Planetary Development, better known as RX, and other organizations won't try to retrieve more samples, but they still don't even know how the water was found in the first place. But with Luna and a few samples, Song, Hong, and other like-minded researchers could potentially discover the answers for themselves.

For people like Captain Han, Director Choi (Gil Hae-yeon), and Ryu Tae-suk (Lee Joon), their desperation to find an answer, whether it be for the survival of Han's daughter, to save the population of Earth, or simply to improve their own status, makes them willing to do anything to make lunar water it. They need lunar water to be the thing that saves everyone, just as Song's sister did. Won-kyung dreamed of the "silent sea" years before Balhae Station, so once she discovered water there and felt that hope, she held tight, and soon enough she crossed serious moral boundaries for a future she didn't even know could exist. 

In the case of Song and Hong, the two doctors who represent the other end of the spectrum, they believe in the mission to a point. But they also know that there's no miracle cure to the world water crisis, and from the beginning, they are clear about their value of human life. As the two who are questioning everything from the very first mission meeting, Song and Hong know to ask whether it is really worth it, especially after witnessing firsthand how brutal and deadly lunar water really is. While Song would love for the water to be the ultimate cure, she isn't willing to sacrifice the lives of those around her just for some dream. 

Basically, everyone is using the future that they think lunar water can give them as an excuse for the atrocities they commit, whether this be experimenting on clones, covering up the deaths of a whole crew of people, or killing the witnesses on the mission, as Ryu attempts to do.

Throughout Season 1, Captain Han shares the same pragmatic, logical understanding as Song, but he has his daughter to fight for, so he's willing to do almost anything to complete the mission. But then enters Luna, a superpowered little girl who is desperate to keep the lunar water to herself, so much so that she tears one of the team member's arms off to get it. Song sees through the violence and realizes that it's not a monster attacking them, but a girl who can survive the water. Through further investigating, it's discovered that the Balhae crew were experimenting with the water on numbered clones known as "Luna." Each time, the girls died, until number 73, which is the Luna the crew meets upon their arrival. 

Even after discovering all of this, Han still has one goal, and that's finding the samples and bringing them back to Earth, even if that means killing the "intruder" — Luna. But once they meet face to face, Luna is the final straw for Han, bringing him to his senses about what's really important. She reminds him of his daughter, who looks to be around the same (physical) age and desperately needs water to survive. The entire reason he goes on the mission is for her, but Luna reminds him that there are other children and other people that matter just as much, and she's one of them. While the water sample is still a major priority, Luna's survival — and the hope that she can live a real life — is the true mission.

There are plenty of unanswered questions at the end "The Silent Sea" Season 1. The two biggest mysteries are Luna and lunar water, as there's still not a lot known about either. In the penultimate episode, Ryu insinuates to Han that there's much more about the original Balhae mission, and the lunar water itself, that they don't know, saying, "You have no idea what happened here and what the lunar water is" — and he's right. As Ryu is one of the soldiers who left the original Balhae crew to die, the show hints at him knowing more, with the events revolving around that fateful day being very important. For example, if they were finding success with Luna 73, what really led Choi to randomly shut down the study?

Of course, there's also everything about Luna that we don't know. While she can clearly survive the lunar water, it doesn't just sustain her, but it also gives her advanced healing, speed, strength, eyesight, and probably a lot more. Oh, and she can also breathe in the moon's atmosphere, no big deal. So how does all this happen? We see the experiments that led to Luna 73, but not much else about her background. As for her connection to the water, Luna's bite allows Song to survive the water's infection, but what else might it do? It's clearly very powerful and might serve a bigger purpose for human survival than just quenching thirst.

Although "The Silent Sea" Season 1 ends with only a few of the original crew left standing and a rescue ship arriving, the events after that are unclear. Early on in Episode 8, Song declares her plan for Luna and herself, stating that she will escort them both to the International Institute of Space Biology, which appears to be a satellite or other structure in space that serves as a neutral organization fully devoted to science and improving the world, without shifting alliances to countries or organizations. The show provides a short look at the IISB, though nothing else about it is revealed.

As Song states that they can't bring the sample or Luna back to Earth, we can assume that she enacts a plan to get to the IISB, which would likely be explored in Season 2. Even though it portrays itself as neutral territory, there will probably be trouble there as well, which would set up for drama in new episodes. Also, there's no way Choi or RX are letting this resource go without a fight. 

There's also the question of whether or not to reveal the truth about Balhae Station, which is brought up earlier in the final episode. Both Hong and Song want to put the truth out there so that everyone knows what really happened to people like Won-kyung and Soo-chan, but this would likely have huge ramifications on them and those they care about. Overall, there is plenty left to explore if Netflix decides to greenlight a second season of "The Silent Sea."