It is 3024.Hundreds of the greatest nuclear bomb expert in the world hate everybody except themselves.So they begin to build cobalt bomb.Cobalt bomb is a kind of nuclear bomb.They also use fusion to detonate.It's similar to an atomic bomb，but a single one can wipe out the entire planet. If a cobalt bomb detonated at the stratosphere，then it‘s radiation would wipe out all life on earth.

Actually the hundreds of the greatest nuclear bomb expert in the world are aliens from the centauri level one civilization. They have been lurking in the bodies of those people for a long time,after a century of observation, they found that the human developed too fast. In the beginning they were only level0.4, but now they were level 0.7. If it continues like this,it will be a threat to their civilization. So they tried to eradicate the earth.

The aliens under the guise of testing a nuclear bomb, go to the North Pole to build cobalt bomb. They put a hydrogen bomb into cobalt 59, and then wrapped the shell of an atomic bomb around it. They test the bomb in the North Pole,but it didn’t blow up. With several surveys, they found out that there weren’t enough cobalt 59. But they can’t get more cobalt 59,so they use uranium 235 instead. Uranium 235 is the ingredients of atomic bomb, but isn’t the cobalt bombs,but they don’t have anything else,so they can only use this.

At last the aliens built the cobalt bomb.When they are ready to blow up,suddenly,EH appeared. He fired a laser and the aliens are ready to fight. They fight in this way.Finally the aliens lost, EH dismantled the cobalt bomb, and saved the world.