The play is based on the real revolutionary experience and outstanding achievements of Cai Wei, one of the founders of radio communications during the Red Army period. It tells the story of the unknown heroes who fought against the enemy in the decryption and anti-decryption of radio codes and made great contributions to the victory of the Red Army's Long March. After the April 12 counter-revolutionary coup, Cai Zeliang returned to Shanghai to find the organization. In order not to expose the identity of his family, Cai Zeliang used the alias Cai Wei and met Mingsong, Xia Tian and others from the Special Branch of the Communist Party of China in a radio training class. In the process of our party's preparation for the establishment of the first red radio station, Cai Zeliang's party membership was confirmed and he officially joined the radio station construction work. Later, he was ordered to go to the Hubei-Henan-Anhui Soviet Area with Xu Zhengye, Qu Xiangdong and others to prepare for the establishment of a radio station. Arriving in the Hubei-Henan-Anhui Soviet Area, Cai Wei played his radio expertise and, together with Xu Zhengye and Qu Xiangdong, established the first radio station for the Red Fourth Front Army and trained a group of radio talents. After the radio station was operating normally, Cai Wei was not satisfied with the radio station being only used for sending and receiving messages. He also thought about the mission of eavesdropping on the enemy's military intelligence. He used his knowledge and understanding of the enemy Huang Jibi to decipher the KMT's codes again and again, and timely understand the enemy's troop movements, providing strong intelligence support for the Soviet Red Army to defeat the enemy. When the Long March was about to meet in victory, Cai Wei sacrificed his precious life at the age of 29 in a small border town in Gansu due to overwork.