The protagonist Gao Jingtian witnessed an incident of a girl falling from a building on campus, and was commissioned by Fan Xiaoqing, a friend of the girl who fell from the building, to find out the real reason why the girl fell from the building. A seemingly ordinary suicide incident was closed by the school and the police as a depression suicide. However, as the protagonist discovers and investigates step by step, he discovers that there are many unknown secrets hidden behind this incident, revealing the pitiful and sad fate of the girl who fell from the building. In the end, Gao Jingtian finally found out the culprit who caused the girl to fall. In the tracing process of the entire incident, the strength and faith of people living at the bottom of society also changed the values of Gao Jingtian, a wealthy family, and thus found the direction of his own life.