A good storytelling is essential to make a computer game more immersed and appealing as it impress the players emotion. The Storytelling consists of many factors. Among them, the Plot, or the flow of the story (Story-flow) is significant. The 'Call of Duty' is a successful computer game in the aspect of the story-flow. In this paper, the way to apply traditional theories about the story-flow to this game is analyzed. And an applying policy of traditional story-flow theories to computer games is presented.