Riko, Reg, and their new friend, Nanachi, continue their journey down the Abyss and arrive at the 5th layer. But in order for them to continue to the 6th layer, they must encounter the haunting figure of Nanachi's past: Bondrewd the Novel. A continuation of the epic adventure of plucky Riko and Reg who are joined by their new friend Nanachi. Together they descend into the Abyss' treacherous fifth layer, the Sea of Corpses, and encounter the mysterious Bondrewd, a legendary White Whistle whose shadow looms over Nanachi's troubled past. Bondrewd is ingratiatingly hospitable, but the brave adventurers know things are not always as they seem in the enigmatic Abyss.