This paper applies plot analysis, a traditional method of humanities narrative analysis, to realize a quantitative narrative structure and conducts a quantitative analysis of the result. The validities of plot divisions and a classification are evaluated numerically by calculating identity frequencies through plot analysis which is a technique employed within the humanities. The serial patterns of the narrative structures are extracted by utilizing the n-gram method on the results of a plot classification. Period transitions within frequent plots are also extracted using the chi-square test. Moreover, theme words for the stories are extracted using a quantitative technique that analyzes the relation between theme and plot, and the stories are subsequently classified according to the themes. The plot characteristics for each theme are also extracted based on the theme-classification results. This is not a completely automatic method because the divisions and the classification were created manually, albeit by utilizing the quantitative index. However, it is expected that the techniques reported in this paper can form the basis of a completely automatic method for analyzing stories in the future.