Neppuu Kairiku Bushi Road

A poison known as "shinobi," delivered to Earth by an asteroid, has left the world in despair. Survivors flee to "Kairiku," a region once beneath the ocean, in an attempt to avoid the poison's effects. Ame, a princess from a destroyed kingdom, seeks to restore hope by obtaining the "Holy Weapon Giga Road" and uniting with the legendary warrior Yagyuu to combat the poison and save the world.