Tsutomu, an ordinary middle school student busy studying for the high school entrance exams, encounters a man fleeing from someone and gets caught up in the chase. Amid the confusion, he is accidentally killed. Fortunately, Birdy (an interplanetary agent) knows a way to save him, though unfortunately, this requires merging their bodies into one. Consequently, he is now stuck with this officer, accompanying him on the ride as they capture criminals and save lives.