In recent years, IP adaptation has developed rapidly in China. The change of suspense reasoning theme has experienced a long process from silence to rise. Now it has become one of the most popular types of dramas in the online drama market. Since 2020, the three suspense reasoning novels of Chinese writer Zijin Chen have been adapted into online dramas successively, and the three adapted dramas have achieved excellent results in the Chinese online drama market by virtue of their story creativity and excellent production level. This paper takes Zijin Chen's novel "bad boy" and its adapted online drama "hidden corner" as the research object, and makes a cross media narrative study on the differences in plot structure and character writing between them, This paper analyzes how the screenwriting team of the film series changes the plot and constructs the story world of the mother story through the deletion of the plot narrative and the transformation of the narrative perspective, and puts forward the strategic conception of the online adaptation of the suspense reasoning novel.