Young Kengo Manaka lives on Mars. As he lives out his peaceful, day-to-day life, the monster Golba suddenly appears, throwing the town into chaos! Meanwhile, Kengo has a fateful meeting with a giant stone statue sleeping deep beneath the ground on Mars. When Kengo becomes one with an Ultra-Ancient light, his destiny is forcefully thrown into motion!

After Kengo comes to Earth to become a member of the defense team GUTS-Select and protect people from monsters, the Vampire Monster Gymaira appears! To make matters worse, the second Giant of Darkness, Darrgon, has been resurrected! In the face of such overwhelming strength, Trigger has no choice but to increase his own strength too – and that's when a new power awakens !!

Carmeara finally gets a hold of the Eternity Core and is transformed into the repulsive form of the Evil God, Megalothor! Then, the dark energy she emits begins to engulf the world… at this rate the Earth is doomed! To save the world from imminent darkness, Kengo and the crew’s decisive battle begins!