The five girls of ITZY are new members of Gangnam Underground Network-GUN for short-a similar covert organization of idols like the IPG led by PSY, intending to take down Lee Kangdae from within. Would they be able to maintain a normal life of friendship, career, and love while also entangling themselves in the world of espionage and oppose arguably the most powerful man in Korea in 2028? And would the identity of the cunning Black Mamba be revealed eventually? How would the fact that Kobayashi Sachiko was essentially the god-AI Naevis impact their fight for good? Lovesick Monster Universe Phase Two continues with Book 5: Checkmate.