After the successful deployment of Gravion's ultimate attack, the Zeravire threat appeared to dissipate temporarily. However, when the Zeravire suddenly resurfaces, the Earth Gult and their trump card, the super robot Gravion, are once again called upon to defend their world. Meanwhile, the EFA is working to develop their own weapons, the Grand Trooper, in order to counter the Zeravire. As they prepare to battle once more, the Earth Gult and EFA must not only safeguard their future but also confront their pasts and unravel the many mysteries surrounding the Zeravire.