In 1937, the Battle of Songhu broke out and Shanghai fell. Ji Mingyuan, a 23-year-old Cambridge mathematics genius, gave up his invitation to Princeton and returned to his war-torn motherland with his knowledge of probability models and cryptography.
Under the iron heel of the Japanese army, he formed an underground intelligence team code-named "Ghost" and used mathematics to construct an invisible war - he used probability to predict the Japanese army's actions, used music to convey encrypted intelligence, and used false data to induce the enemy into a fatal trap.
However, his opponent, Japanese intelligence officer Ichiro Sato, was also proficient in mathematics and game theory. The two started an intellectual duel with life as a bargaining chip in a cafe in the concession, a confessional in a church, and a concert at the French Consulate.
When his comrades sacrifice one by one, and when cold calculations encounter unquantifiable human nature, Ji Mingyuan must face the most difficult proposition: In the chaos of war, can mathematics calculate hope?
