A few years after the events of the first title, Tsumi occurs in the fictional Sumaru City. The main focus of the game is the subjective nature of reality, with rumors holding the power to literally alter the face of reality and change the world itself.
The protagonist of the story is a young High School student, Suou Tatsuya, whose path becomes intertwined with two other students, Mishina Eikichi and Lisa Silverman, as they encounter the enigmatic, rumored Joker-sama, a mysterious being who will appear before anyone who calls themselves on their own cell phone, and offers to grant their deepest wishes. Anyone who fails to tell Joker-sama their wishes, either because they lack one or do not wish to tell, will have their life energy stolen, turning them into Shadow People. Upon meeting the three students, Joker-sama is angered that they do not recognize him, as he claims they have done something horrible to him in the past. Swearing revenge, he departs, leaving the three students confused, and eager to investigate about this Joker-sama, after they have released their Personae and met with the enigmatic Philemon.