Racing against time as the research station falls under destruction, the surviving crew members decide on the fate of the mission — and their own.

The crew's initial findings are at odds with their knowledge of the research station. Split into threes, the members set out to look for the sample.

Ji-an's body cam captures a startling moment of life and death. Submerged in sweat, Gong Soo-chan shows worrisome signs of an unusual infection.

E2, Ryu Tae-suk and the samples go missing. Seeing a familiar name on the intruder, Ji-an follows her down the vents for answers.

Han Yun-jae updates the director and gets access to a restricted area. The crew learns of the sample's powers and the true motive behind their mission.

Recalling her sister's encrypted message, Ji-an searches the database for Luna. A young intruder and a double-crosser emerge from the shadows.

Ji-an opens a hard drive that chronicles Song Won-kyung's life and work on the station. Meanwhile, others uncover the remains of the experiment.