Nagisa, Honoka, and Hikari have been called upon by the Brave Fighters of the Garden of Hope. Their mission is to safeguard the realm from a malevolent sorceress who seeks to pilfer the Diamond Line, a precious set of adornments worn each year by the queen to replenish the kingdom's water supply during a ceremony. Should the witch succeed in reviving the Dark Lord, devastation will ensue not only in the Garden of Hope but also in neighboring galaxies like the Garden of Rainbows and the Garden of Light.