The anime centers on four girls at the full bloom of their youth, working hard to achieve their dreams as they struggle valiantly. In Japanese entertainment, Maesetsu! refers to an introductory talk or explanation addressed to the audience before the broadcast of television programs, usually performed by assistant directors and particularly comedians in variety or comedy shows.

After surviving the brutal challenges of Idofront, Riko now possesses a White Whistle, allowing her to descend into the Abyss's sixth layer—The Capital of the Unreturned. Alongside Reg and Nanachi, Riko begins to explore the uncharted domain, where the ruins of the promised Golden City are located. As the trio starts to adapt to the harsh environment, they soon encounter dangerous creatures and treacherous landscapes. Their expedition leads them to a village inhabited by strange beings known as "hollows." Despite the creeping sense of unease that welcomes them, the three venture onward to uncover the mysteries of the settlement and long-lost legacies of the forgotten adventurers who once descended into the horrors of the unexplored Abyss.

Walküre and Delta Flight used music to save people from the Vár Syndrome, a previously unknown disease that made humans and others go berserk. However, they find themselves facing a new threat…

Second season of Machikado Mazoku.