

Season 1 • Episode 1
LatestA math genius gets recruited by Chinese spy agency to crack a complex coded message in the early republican era.
A math genius gets recruited by Chinese spy agency to crack a complex coded message in the early republican era.
Acting
Chen Xuedong's obsessive, twitchy mathematical isolation
Production
Gorgeous Republican-era sets that feel lived-in
Writing
Actually coherent cryptography that doesn't insult your intelligence
Trivia, insights & behind the scenes
The ciphers blend real historical Chinese cryptographic methods with fictional ones; consultants included actual mathematicians.
Based on Mai Jia's novel, part of a wave of Republican-era spy dramas that let Chinese audiences process wartime trauma through puzzle-box narratives.