Kono Subarashii Sekai ni Bakuen wo 2023, One year before a certain useless goddess and NEET extraordinaire hit the scene, Megumin, the "Greatest Genius of the Crimson Magic Clan," is hard at work. Ever since a life-changing encounter in her youth, the young wizard has dedicated her every waking moment to the pursuit of the ultimate offensive magic: Explosion magic. Well, every moment not spent hustling food from her self-proclaimed rival. While the big sister's away, the little one will play too and on a routine trip into the woods, Megumin's little sister, Komekko, finds a strange black kitten. Little does she know that this cat plays a key role in unsealing a Dark God's tomb.