"The Silent Sea" is a Korean adventure series that takes place in the near future. After an apocalypse, Earth is facing a shortage of water and provisions, putting humanity at the brink of destruction. One of the soldiers from a space agency becomes part of a special operation. A group of astronauts is sent to the Moon to retrieve mysterious water samples from the "Silent Sea," a long-abandoned space station. Yun Jae believes that the safety of the group is paramount.