Facing the threat of the Qin State, danger seems to lurk within the Han State, which is known as the weakest out of the Seven States. Unknown to the Han Emperor, that very threat is the Great General of Han, Ji Wuye. Working under the Great General are the Four Fearful Warriors of Nightfall. Each four specialized in military, finance, politics, and espionage. In hopes of creating a new Han State, Quicksand was formed by Han Fei, the ninth prince of the Han. With Wei Zhuang, Zhang Liang, Zinü, and Nong Yu, they support the Prince in realizing the goal of Quicksand while being drawn into a whirlpool of power named “world”. (Source: wikipedia)

The fourth season takes place after the Mechanical City has collapsed and the Mohists are almost eliminated. The Qin Empire plans for a period of peace and prosperity and the Emperor utilizes a huge amount of labor to build the Great Wall and plans more sophisticated programs. There is apprehension in the city about the function of the giant boat Mirage which appears off the coast. Various rebel factions came together in Shanghai to defeat the Emperor's ambition. The Emperor and his forces, including the Quicksand group, the Yin-Yang School, Net Trap Organization and swordsman Shengqi are all arraigned against the rebel group comprising the Mohists, Confucianists and the Taoists. Tianming's education and training continue as he is faced with more and more challenges as leader of the Mohists. (Source: Qin's Moon Wiki)

In the second season, Emperor Qin sends Quicksand to destroy Machinery City, the home of the Mohist School. At the same time, Duanmu Rong sends the three kids, Tianming, Shao Yu, and Gao Yu, into the forbidden grounds of the Mohist School, a place where nobody could enter without permission. (Source: AniDB)

An indentured Chinese laborer, brought to Japan to work in a coal mine during WWII, manages to escape his captors. He hides out in the Japanese countryside, so far from human habitation that he does not realize when the war ends, with ultimately tragic results. Based on a story by Yoichi Takashi.