In the autumn of 1948, the People's Liberation Army was about to cross the river. The Shanghai Underground Party of the Communist Party of China received an almost impossible task: to send a top-secret intelligence (codenamed "Homecoming") about the "Comprehensive Deployment of Yangtze River Defense Fortifications" out of Shanghai and to Jiangbei via a secret radio station. But at this time, two of the three secret radio stations in Shanghai had been detected by the Kuomintang Secrecy Bureau. The core component of the only intact secret radio station "Nightingale" is damaged, and it can only be repaired by finding the "Father of Nightingale" - radio engineer Chen Xinghe (codename "Clockmaker") who has been missing for three years.
