The warriors of the Garden of Hope have called upon Nagisa, Honoka, and Hikari to defend their realm from a sorceress who intends to seize the Diamond Line, which is an ensemble of precious stones worn by the queen during an annual ritual for replenishing the kingdom's water supply. The witch plans to revive the Dark Lord, and if she succeeds, not only will the Garden of Hope be annihilated but also other realms in the galaxy, including the Garden of Rainbows and the Garden of Light.