It tells the story of locksmith Du Ding, who is identified as the "voice thief" by a recording-enabled mute box, and patrol recorder Qiao Cuo, who is ordered to investigate. Teaming up and guided by secondhand dealer Ge Suan, they enter the bell tower and the echo tower, discovering that the city's sounds are being rewritten. Three gears, a future voiceprint, and a cancelled father lead to layer upon layer of twists in the clues. Seven days later, the reboot is imminent, and Du Ding must choose between forgetting and the truth. Who stole the city's names, and who stole Ding's one second?