A Kuomintang agent's spy career during the War of Resistance against Japan

Espionage during the War of Resistance Against Japan, the Military Intelligence Bureau, and the cunning and opportunistic nature of the characters—all prioritizing personal safety and comfort, devoid of heroism. Han Zhenhua, a modern high school graduate, unexpectedly travels back to Shanghai during the War of Resistance Against Japan in 1937. He discovers that although his cell phone has no signal, its AI software works, becoming his greatest advantage. By chance, he is mistaken by the Military Intelligence Bureau as an external intelligence agent codenamed "Crow." He then uses the intelligence he finds on his phone to provide accurate information about the Japanese and their collaborators, gradually rising from a nobody to a top-tier Military Intelligence Bureau agent hidden in the fog of war. Enraged, the Japanese conduct a massive investigation of all intelligence systems, but find nothing, because his advantage lies in his cell phone's search function—he doesn't need to work for any Japanese intelligence agency!