"Back Against the Devil" is a film about anti-telecommunications fraud, where the entire story evolves from a false mobile telecom scam into a kidnapping and murder case, filled with dramatic twists and turns. The film depicts how, in today's technologically advanced era, some criminals use mobile phones and the internet to commit fraud. According to data, there are 38 different new types of fraud methods in today's society. The protagonist, Fan Yan, and his accomplice, Dao Sang, set a trap to defraud entrepreneur Zhao Ronghai using these new fraud techniques. After contacting Zhao Ronghai's wife, Li Shunan, they demand a ransom of one million yuan in exchange for Zhao Ronghai. During the transaction, Li Shunan receives a call from an unknown number, and when Fan Yan sees her hang up, he prepares to reclaim the ransom in anger. Obsessed with money, Fan Yan drives into Li Shunan, knocking her down to seize the ransom. From that moment on, Fan Yan and Dao Sang find themselves unwittingly involved in a kidnapping case.