The story revolves around four real men who are all members of a special forces unit, known to the public as "sea devils." But in reality, these heroes can be called knights of different elements: they can carry out their professional tasks on land, in the air, and in water. Each of the men has their own unique character, but they are all ready to fulfill their duty regardless of danger and risk. They are intimately familiar with concepts such as brotherhood, friendship, dignity, and honor.