Here is a concise summary of the text:
A group of modern Korean soldiers and a scientist are sent back to the year 1572 by a comet. They meet a young thief who is destined to become a legendary general. They try to help him and the villagers fight against the invaders while looking for a way to return to the future. The scientist manages to go back with a nuclear warhead, but the soldiers stay behind and become part of history.
Here are some key facts extracted from the text:
1. Dr Kim is a researcher working on a project to create a warhead for North and South Korean joint forces.
2. A massive comet passes dangerously close to Earth and causes a time rift that sends three North and three South Korean soldiers and Dr Kim to the year 1572.
3. They meet Yi Sun-sen, a legendary Korean warrior who will later defeat the Japanese invasion, but he is currently a lowly smuggler and thief.
4. The soldiers train Yi to become a general and help the villagers fight against the Jurchen invaders, who also have the missing nuke.
5. Dr Kim discovers that the next comet will pass in four days and they can return to the future, but most of the soldiers decide to stay behind and fight.
6. The soldiers and the villagers win the battle, but many of them die, including Major Kang. Dr Kim returns to the present with the nuke and reports her experience.
7. In the last scene, Yi is shown as the general leading the battle of Myeongnyang Strait with Park and Choi as his staff officers.