After getting dumped by her boyfriend Kentaro, Tomita Momo, who works at a library, suddenly discovers the existence of her ex-boyfriend's current girlfriend Riko through his social media. She is intrigued by Riko, who is the opposite of herself in terms of fashionable sophistication. For "a certain reason," she goes to see Riko in person. Momo confronts Riko and asks, "Do you know what revenge porn is?" And "I want to get back the secret photo data of the two of us that he took... Also, haven't you been taken as well...". An ex-girlfriend and a current girlfriend. Now that these two unlikely lovers have met, their "secret complicity" is about to begin.