Which idiom can be used to describe the movie Nobody?

The film Nobody can be described by the idiom "treading on thin ice". A step-by-step approach is usually used to describe action and caution. "Unknown" is a spy film, which needs every agent to do it step by step. Unknown tells the story of19411February 7, when Japan attacked Pearl Harbor. The next day, Wang puppet government followed Japan to declare war on Britain and the United States, and Japan symbolically occupied the whole of Shanghai. With the full-scale outbreak of the Pacific War, China's anti-Japanese war situation has completely changed. * * * Underground party member risked sending information, undermining the peace between Japan and Chiang Kai-shek and safeguarding the motherland.