North Korean officer Major Kang Min-gil (Kim Seung-woo), displeased with the conciliation of the Koreas, steals the warhead with the help of several of his loyal soldiers.

The modern Koreans also meet with a regional foreigner who turns out to be none other than the young version of Yi Sun-sin (Park Joong-hoon), the legendary admiral who later becomes instrumental in the defeat of the later Japanese invasion.

However, this "General" Yi acts like nothing like either of the modern Korean histories illustrate him: he is a petty thief and ginseng smuggler who just failed his military Gwageo exam, and seeing no future for himself, has turned to crime in order to survive.

However, Kang is forced to kill the son of a war leader sleeping in the same tent, and in retaliation the Jurchens initiate movement to violently root out the modern Koreans.

With the warhead back in their possession, and the timing and location of the comet's overhead passing accurately calculated by Dr. Kim, the "Heavenly Soldiers" prepare to leave the past as it currently stands.

When Majors Park and Kang debate over the strategy that would work best for the villagers, Yi, beginning to find his legendary tactical competence, successfully argues for a combination of ambushes and a last stand.