The underground kingdom of La Grande has existed for thousands of years, unknown to the people of earth. It is a home to magical creatures and mythical races, where dwarves and fairies live together. That peace was shattered two days ago when a man from the surface, Dr. Shu Shirakawa, murdered seven people and fled with an artifact known as the void crystal.
One of the guard captains, Tentoumushi, is dispatched in her Magic Soldier the Tonbo to retrieve the artifact and bring Dr. Shirakawa to justice.
The Kurogane pursues the fleeing command carriers into the Atlantic Ocean and, by chance or fate, encounters Tentoumushi. Together they pursue to command carriers through a cloaking field to a mysterious island floating on the surface of the ocean.
Rather than withdrawing to request reinforcements and risk the enemy slipping away, Captain Minase decides to press their advantage of surprise and attack. The enemy unveils a new weapon, the dreadful Granzon, armed with singularity based weapons that could only have come from the void crystal.
The pilots narrowly manage to disable the Granzon, sinking it into the ocean, but in that time the rest of the enemy has fled. However, after the battle Chen makes a startling revelation: during the battle he teleported directly into the enemy hangar and sighted not just Elzam’s modified Lion, but the Grungust Zero an another SR Class prototype as well.
The CDF remain at large with three highly dangerous machines. The battle is far from over.