Somewhere in the south of the island there is a creature waiting Jeju 2 km deep into the sea. Eclipse is a platform drilling rig stationed at Sector 7, a mining area located in the southern island of Jeju.
Dupe you fail the mission to find oil drilling in the headquarters crew gives the order to withdraw. Captain Jeong-man team is sent to supervi withdrawal. However Hae-jun, crew manager, stand stubbornly orders headquarters, being convinced that it will reveal an oil field in Sector 7. Convinced by Hae-Juns captain crew suggested to make another last attempt.
When manager and crew were focused on finding oil lost communication with headquarters and the entire team is overwhelmed by the feeling that there is something dangerous in the water. When people start to disappear one by one, the survivors are forced to fight for their lives in a race to the death with the sea monster. Survival seems impossible, but the crew is ready to do anything to stay alive.