Modern tactics instructor Zhao Xu was hit by a meteorite and arrived in Kaifeng of the Song Dynasty. When he woke up, he was caught up in the siege of the Jin army. The female catcher Zhou Qinghe suspected that he was a spy, but during the investigation, he discovered that the meteorite was related to the conspiracy between the DPRK and China. Taiwei Cao Ji secretly communicated with the enemy. The noble daughter Cao Yunshu wanted to use gunpowder to prove herself. The painter Zhang Zeduan chased and reported the witchcraft, and the singing girl Liang Hongyu handed over a blood-stained silk book. Zhao Xu has to find a way between defending the city, solving crimes and surviving, and that meteorite seems to be the answer to all the puzzles.
