After successfully bringing another nation into their sphere of influence, Light and Princess Lilith now have all the backing they need to carry out their plot of usurping the current ruler of the Human Kingdom—Lilith's father—and installing the princess in his place. And their timing couldn't be more perfect, for not only are high-ranking representatives from every nation converging on the Principality of the Nine for an emergency summit, Light's adventuring party—the Black Fools—has also been promoted to A-rank, meaning they will be in attendance as Princess Lilith's bodyguards. Furthermore, one of the delegates attending the summit representing the Demonkin Nation just happens to be Diablo, one of Light's former partymates that Light has sworn vengeance against for betraying him. Will Light manage to pull off the double whammy of strengthening his hand by installing someone more sympathetic to his cause on the throne of the Human Kingdom and cross a sixth name off his revenge list?