The Balhae Cover-Up: The SAA claimed Balhae Station was abandoned due to a fatal nuclear radiation leak. In reality, researchers discovered Lunar Water—a substance that multiplies exponentially when reacting with blood or biological matter. Exposure causes individuals to drown internally as their lungs fill with self-replicating water.
Human Experimentation & Luna 073: To exploit Lunar Water without killing humans, Dr. Song Won-kyung and the research team cloned human children to test adaptation. Subject 73 (Luna) was the sole survivor who successfully bonded with Lunar Water, gaining rapid cellular regeneration, heightened physical traits, and the ability to process Lunar Water safely.
Corporate Sabotage: Engineer Ryu Tae-suk was part of the original military detachment sent five years prior to purge the base and kill the scientists to cover up the illegal research. On this mission, he worked for RX (a private transnational corporation) to steal the sample vials for private profit.
The Climax & Finale: As Lunar Water breaches containment and floods the facility, Ryu Tae-suk is killed. To ensure Dr. Song, Dr. Hong, and Luna can reach the evacuation point, Captain Han steps outside into the lower chamber to initiate a manual airlock purge. The water pressure blows him out onto the lunar surface. Dying on the moon's surface, Han watches Luna walk up to him without a helmet or spacesuit—unaffected by the vacuum or cold due to her adaptation. Dr. Song and Dr. Hong emerge, holding hands with Luna as an international rescue ship lands to retrieve them.