Adapted from the novel of the same name by Zhihu author Xu Jiuwangchuan, it tells the story of Concubine Su Qin (played by Huang Yang Tinian) who suffers from a strange disease. After being banished to the cold palace, she was kidnapped by a man in black who was "sick within a disease". He reached a "regicide" agreement with the regent Lu Huan (played by Zhang Jingyun) as a condition for her to stay together and marry him. In the assassination storm, the two went through life and death together and their feelings gradually warmed up. As the true identity of the man in black was revealed, the two finally fell in love and stayed together.