Two soldiers vanish due to an unknown attack. Sergeant Dongjin is a war dog, hence goes in an operation to find those soldiers, while he encounters his ex girlfriend Yerim, who is a first lieutenant.

Dongjin loses his dog Leo during the search. Meanwhile, Yerim finds a rabies mutant virus in the soldier's dead body. Noticing something is wrong, the head of national security orders to form a special force to resolve the case.

Yerim survives from a zombie's attack, and finds out that the virus spreads via blood. Meanwhile, Dongjin accidentally goes to North Korean territory during the search, and as he escapes, he is attacked by an unknown object.

Special force arrives and saves Dongjin, trying to kill the object, but they fail. The object seems to be afraid of water, hence they succeed in putting the target under water, but fails to eliminate it.

As the special forces keep failing, the head of national security is anxious and hides this from the reporters. Meanwhile, Yerim investigates the blood of the unknown object, and the forces continue their search.

Dongjin finds out the conspiracy behind the 1997 incident. Meanwhile, Yerim informs the forces how to kill the object, and eventually the special forces manage to kill the object.