Surgeon Yu Yuan used Renji Hospital as a cover and used thermometers to secretly write intelligence and sulfonamide tablets to lay deadly traps; disabled armorer He Sui hid in a church, with maps hidden in prosthetic limbs and explosives embedded in wheelchair bearings. The two were once lovers who had not yet exchanged marriage letters, but now they have been tempered by the flames of war into the sharpest scalpels and bullets. When Yu Yuan was imprisoned in the Hongkou military camp for intercepting the Japanese bacterial experiment plan and was exposed, He Sui used a wheelchair as a chariot and raided alone with the burning fragments of the marriage certificate. The mercury code in the thermometer, the sulfaphosphonate powder in the sandwich of prosthetic limbs, the contour map of ulcerated wounds - medical equipment has been turned into weapons of secret warfare, and church sacred vessels have been turned into killing machines. They used scalpels to break the situation in the glacier tunnel, detonated explosives with heartbeat frequency in the self-destructed arsenal, and the bloody engagement and the survival of the nation were entangled in the smoke of gunpowder. This is a spy war with medical knowledge as the edge, and a love and hatred in troubled times written with trauma and medicine. When the Red Cross was lost in the flames of war, only the untarnished marriage certificate was left with an eternal vow etched on the shrapnel.
