It has been a week since Momonga logged in to his favorite RPG one last time and stranded himself there. Now he leads his guild as the Ainz Ooal Gown overlord. Finding himself in dire need of better information, he travels disguised as an adventurer to the walled city of E-Rantel, with Narberal the battle maid at his side. The pair accept a mission to retrieve medicinal herbs, making for a forest said to be the home of a great and wise beast. But the sinister influence of a fanatical cabal approaches E-Rantel, and the armor-clad Ainz will face both a ruthless warrior and a legion of the undead!
Nagisa has collapsed! Kojou rushes to the hospital, but suddenly a mysterious girl appears, and she looks just like Avrora, the former Fourth Primogenitor. She backs Kojou into a corner--but is she the real Avrora? Through this encounter, Kojou regains his lost memories, what will he remember? Finally, Kojou's past and the secrets of the Fourth Primogenitor are revealed!