Would World War lll Happen??

I think, World War 3 will happen in my life time soon. The two nations that's going to fight is South Korea and North Korea. I think North Korean spy who can speak Japanese, will enter South Korea to get some information about something. Like, something related to assassination....
Here's my story; The North Korean Spy enters the Prime Minister's house to get some information about assassination of someone.Unfortunately, the South Korean worker in the prime minister's house founds the North Korean spy entering their secret laboratory. When the South Korean worker talked to him to see if he's a stranger or not,the North Korean spy took out the gun and shoots him. Then he runs away. When he got out of the laboratory, he saw the prime minister and five body guards waiting for him with guns. The spy knew it was end of his life, so he shot the prime minister's head and suicide.....

Later, South Korea declared the War to North Korea. But the South Koreans gets killed by the secret atomic bomb that North Korea had. The North Korea dropped the biggest atomic bomb to the middle of the Sea of Japan, and half west of Japan, and almost every part of South Korea is burned. Soon Japan declares a war to North Korea, allying US, (Democrat Nation) trying to stop the war. For the North Korean side, Russia, and China Allies together. But soon the huge influence of the atomic bomb, destroys the most of the north hemisphere, and every countries in the North hemisphere joins the War. In order to end this atomic bomb-war,America dropped the biggest atomic bomb and destroyed whole North Hemisphere....and finally the war ends.
THE END

*Connecting two causes and ideas of World War 1,and 2