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.

Maesetsu! Opening Act

A gemstone named the Mermaid's Scale appears in a secret, underground auction, and Lupin is coerced by the queen of the underworld into stealing the rock for her. Lupin however quickly discovers not only that the stone is a forgery, but that the real Mermaid's Scale is part of an unsolved riddle involving the mysterious girl Misa that leads to transcending mortality.