The Hollow Earth Chronicles

A chance discovery of a large crevasse at the North Pole in the 1800s took our intrepid explorers into another world beneath the surface of the earth. It became one of the first encounters with people living in a place now called Hollow Earth. A hundred years later, another visitor had a less than friendly encounter. The three races of Hollow Earth had lived in peace for many centuries after a great war. But their world became threatened by a series of underground nuclear explosions that came from the surface. The people on the surface were totally ignorant of their existence and continued their explosions. Despite the Hollow Earth people being very cautious about retaliation, their patience had finally run out by the 2020s. The latest visitor became a pawn in a potential war that threatened every living thing on the surface. The Hollow Earth's advanced technology meant that the surface dwellers were going to be in the fight of their lives, and they had no idea why.