did not take place during that fateful plane hijacking but rather four years earlier, when the Federation Government tasked Siesta with locating a spy in Japan. During her undercover investigation, she happened upon her future assistant, who had a connection with the spy she was looking for. With Kimihiko as her only lead, she enlisted his help in the search. But Siesta hid her identity with constant disguises, so unbeknownst to Kimihiko, he had already met the Ace Detective. Finally, the story of their true encounter--and the reason behind Siesta's invitation to Kimihiko on that day in the sky--is revealed in this prequel!