During the Zhenguan period, Shi Mingyue, the daughter of a merchant, rose to prominence in Duzhijian with her arithmetic skills. However, she was regarded as a thorn in the side of the newly promoted Jieyu Du Ruo because of the discovery of evidence of corruption at the Du family silk and satin shop. The Du family's father and daughter colluded with the powerful, secretly made royal objects, smuggled arms, and even designed to have Shi Mingyue thrown into the dungeon of Dali Temple. At the same time, Wang Jingshu in the Shi Mansion drew a clear line with the Shi family in order to protect herself. Shi Ruyue was banned but still risked her life to pass on clues.
Using abacus as a blade, Shi Mingyue started a life-and-death game with the Du family under the protection of the queen. She peeled off clues from the tampered tax roll numbers, borrowed her sister Shi Ruyue's calligraphy talent to build momentum, and used her mathematical wisdom to solve the smuggling mystery on the Western Region trade routes. When the jade seal, blood-stained account books and hidden honeysuckle patterns gradually piece together the truth, a battle concerning the survival of the family and the purity of the court suddenly begins within the red wall. In the whirlpool of conspiracy and betrayal, can the Shi sisters use their calculations to clear the fog and restore peace to the city of Chang'an?
Purpose: Focus on the struggle of little people in power and conspiracy, the power of women to help each other, and the belief that justice will eventually break through the darkness.