Using a huge pile of Mananite to power up Megumin's Explosion, Kazuma's party blows a hole into the barrier surrounding the Demon Lord's Castle. But after reconvening with Aqua, our intrepid heroes will have to answer an important question before they settle things once and for all... Just how much cash can they expect for bringing the Demon Lord down?  In the final volume of the hit action-comedy, a cowardly NEET and Axel's favorite bunch of misfits steel themselves for one last battle!