A low-grade goddess turned arch priest who works hard to acquire party trick skills, a disappointing arch wizard who can only unleash explosion magic once per day, and Kazuma himself, whose only redeeming quality is his good luck. Kazuma despairs over the completely useless party that's been formed.

Dullahan, a top leader in the Devil King's army, yet again appears at the city in a frenzied rage.

The rampaging ancient weapon: the mobile fortress, Destroyer, is headed straight for Kazuma and party's city!

Evading the angry mob, the gang discover that the source of the town's water is being poisoned by the man from earlier, who is revealed to be one of the Devil King's army leaders, Hans the Deadly Poison Slime.