夏日心跳

The world has fallen into despair after being devastated by a deadly poison called "shinobi," which arrived on Earth via an asteroid. Survivors flee to "Kairiku," a refuge that was once the ocean floor, where they struggle to shield themselves from the poison’s effects. Yet in this bleak world, a glimmer of hope remains-the legendary "Holy Weapon Giga Road" and the warrior "Yagyuu," said to be the key to countering the poison. To save what’s left of the world, Ame, a princess of a ruined nation, rises to take action.