The scientific research submarine "Comma" is a die-hard fan of the science fiction novel "Journey to the Center of the Earth". In order to study the mysterious substances on the seabed, he followed his uncle, the geologist "Iron Stone", into the Mariana Trench. He was accidentally drawn into a cave maze and came to a huge unknown world and discovered ancient creatures, which started an unimaginable exploration of the seabed and the center of the earth.