It's 1448, the 30th year of Se Jong's reign. The Ming dynasty's meddling into Joseon's domestic affairs goes to extremes, and Se Jong secretly plans to develop Singijeon, a rocket weapon upgraded from Goryeo's firearms technology. The Ming finds out and quickly dispatches assassins to attack the research lab, but Choi Hae San, the man in charge of the project, destroys himself along with the research materials to protect the weapon's secret.
