Do bluebirds know the true nature of happiness? Al, a con man, and Efi, a dragon girl who materializes "lies" and eats them as food, arrive in Indigo Town to search for a "blue bird" that will make any wish come true at the request of a familiar informant. The two rent a room in a large mansion where Misha, who is loved and called "Diva" by the town's residents, lives, and proceed to investigate the "Blue Bird". As the investigation progresses, Al notices an unsettling atmosphere that covers the city. There is a rumor circulating in the city that a supposedly dead person is walking the streets. The residents of Indigo Town suspect each other of being monsters. What is really going on in this town? And what is the true identity of the "blue bird"? The extra stories "Ephina's Investigation" and "A Certain Dragon's Memoir" are also included! (Source: PHP Institute, translated)