Lin Mo, a mathematical genius, was recruited as a military translator and responsible for cracking Japanese military codes. During her work, she discovered that the Japanese army planned to destroy the Chongqing Arsenal, but because there was a traitor within the military command, the information could not be passed on. She met Chen Mo, an underground member of the Chinese Communist Party, and the two took risks to bypass the traitor and deliver the information, but Lin Mo fell into the suspicion of the military commander.
