Annoyed that Megumin had still been using his castle for explosion practice, Verdia, after proving easily susceptible to Aqua's purification magic, summons an undead army which is quickly defeated by Megumin's explosion magic.
Gamer Kazuma dies in a freak accident, and is met in the afterlife by a crass goddess, Aqua.
With their members being perfectly suited for the job, Kazuma's party, along with Wiz, are chosen to lead an attack against the Destroyer.