The second Korean War

Fantasy
After the United States and South Korea confirmed that North Korea had developed nuclear bombs and weaponry to deliver them the United States and Korea quickly made a plan to take out North Korea. A preemptive strike was launched against all possible launch sites, all airports and the entire border. After the preemptive strike South Korean and American infantry launched a full scale invasion, after which Chinese forces also invaded North Korea to prevent South Korean and American soldiers from ever reaching the Chinese border. After just a few weeks both joint South Korean + American and Chinese forces were both on the brink of starting the final assault, the battle for Pyongyang. Pyongyang fell in just a few days with North Korean soldiers and civilians fighting until the final building was captured. Soon after Pyongyang fell and the war was over South Korean, American and Chinese soldiers all left Pyongyang, being replaced by United Nations peacekeepers. 
After the war the South Korean government started to develop a plan on integrating all occupied territory into South Korea, while China was working on installing a democratic government in Chinese occupied territories.