A trip to the beach isn't fun in the sun for Asta and the Black Bulls—they're on a mission to recover a magic stone! Deep in the Underwater Temple lies new danger and mages with extraordinary powers. But getting in is the first challenge! Luckily, Noelle receives help from a mysterious girl with song magic to master a new spell to help her team. But real danger makes a splash when, Vetto of the Third Eye, storms the temple! He takes out Asta's friends and allies, with unimaginable strength, like they're nothing. Can the magicless mage face all odds and take on the beastly villain?