With the emergency summit at the Principality of the Nine fast approaching, Light must somehow find a way to raise his rank as an adventurer if he is to keep his promise to accompany Princess Lilith there as her bodyguard. Getting the Black Fools bumped up to A-rank in such a short period of time proves tricky, however, and it is only by sheer luck that a quest of sufficient prestige to merit a promotion becomes readily available. Light and the gang soon find themselves traveling by carriage to the Onifolk Archipelago as part of the retinue of the bratty Holy Princess of the onis, Yotsuha, who is returning home from the Duchy. And as chance would have it, the princess is a close personal friend of Oboro, a former member of the Concord of the Tribes. Will Light be able to get his revenge on the oni that betrayed him without jeopardizing his party's mission to raise their rank? And what exactly has the shady, secretive Oboro been up to since the two of them last saw each other?