Lin Yue, a modern communications engineer, accidentally travels back to the Long March era through a mysterious radio wave. Forced to follow the Red Army communication squad as a communicator, he embarks on the twenty-five-thousand-li Long March. From initially just wanting to lie flat and survive, to experiencing the cruel battles of crossing Mount Jiajin and the grasslands and witnessing his comrades sacrifice one after another, Lin Yue sheds his impatience and uses modern communication knowledge to help the troops transmit military intelligence. During the journey, he meets Captain Li Weiguo, who also comes from the future, and comes to understand the Long March spirit through blood and fire. After completing his mission, Lin Yue returns to modern times, carrying the beliefs of the martyrs, comprehending the mission inheritance of two generations of youth, and resolving to continue walking the Long March path of the new era.