After Rabirin, Rate and Asumi watch a volleyball television show, the three decide to take the others out to play beach volleyball. As such, the Healing Animals and the four girls head to a deserted island on a beach volleyball camp. While the others have fun playing, Nodoka struggles to keep up with the other three girls. Meanwhile, Guaiwaru arrives on the other side of the same island and infects a Tree Spirit to create a MegaByogen which he immediately subjects to intense sports training. As a result, Rate does not fully detect the presence of the Byogens until the MegaByogen finally initiates its rampage. The girls transform to engage the MegaByogen but the monster proves to be a formidable foe, having been taught volleyball moves by Guaiwaru. Cure Grace, despite initially failing to pass the MegaByogen's attacks repeatedly, rallies the other Cures before successfully deflecting the monster's attack. All four Cures then work together to defeat the MegaByogen before Cure Grace purifies it and the Tree Spirit. After the battle, the girls all decide to play beach volleyball again another time.