Blue

Two friends in the Korean Navy Lee and Kim are both part of an elite diving squad specialising in emergency deep sea salvage dives Lee is straightlaced and takes his duties seriously while Kim treats the Navy as a lark When Kang a diving instructor and Kims former girlfriend is posted to the unit this creates tension between the friends as they compete for Kangs affections The tension is heightened when Lee is promoted ahead of Kim creating a rivalry between the two Kims gungho approach to diving and the danger he poses for himself and his fellow divers leads to further problems Matters come to a head when an incident at sea causes the sinking of a submarine requiring the unit to attempt a dangerous salvage rescue of the sunken submarine