In the treacherous underworld of Republican-era Shanghai, communist operatives become human torches, burning bright to pierce the darkness. When underground agent Xiao Ke inherits a coded brooch from fallen comrade "Sparrow," betrayal thrusts him into a lethal game of cat and mouse. With renegade vigilante Liu Yunshan as his unlikely shield, they navigate coded qin melodies in ghost markets, outwit double agents at decoy evacuation points, and confront venomous betrayals veiled in camaraderie. Every twist in this high-stakes chess match exposes the razor's edge between sacrifice and salvation, where the brooch holds not just secrets, but the very soul of a revolution forged in blood and valor.