Year 2029: ground on the Mediterranean coast suddenly collapses. "Oxygen" had suddenly disappeared from within the crust, leaving a huge sinkhole 3km in diameter. Since then, more and more "Elements" vanish from the face of the planet. Oxygen, carbon, gold, molybdenum, cobalt... With the elements gone, forest and fields disappeared. Buildings and ancient ruins too. And even life it self.
60 years have passed from that day. The population is a mere 10% of what it had been at it's peak. Tireless investigation and research reveal where the elements have gone : they had flowed into another Earth, the "Negative Earth" on the other side of the dimensional wall.
To save the planet a team of Element Hunters is formed. Every member is a child under 13 years of age. It had turned out that adults don't have the flexible brain tissue necessary to access the "Negative Earth"...