The film is based on the novel of the same name by Mao Dun Literature Award winner Mai Jia. The story is about the 1940s, when the world situation was turbulent and it was crucial to decipher the enemy's communication codes in a timely and accurate manner. Rong Jinzhen (played by Liu Haoran) showed amazing mathematical talent since childhood and was raised by Xiao Lili (played by Daniel Wu), the then president of the university, and his wife Ye Xiaoning (played by Yu Feihong). When Rong Jinzhen entered the university, he was noticed by more people because he solved the difficult problems assigned by mathematics teacher Shees (played by John Cusack), including Zheng Mou (played by Chen Daoming), the director of the mysterious department 701 Bureau. Rong Jinzhen has since entered the door of code deciphering.