Okay kiddo, so a long time ago, there was a big war between two countries called North Korea and South Korea. During the war, some soldiers from South Korea and other countries were caught by North Korean soldiers and taken prisoner.
When the war ended, the North Koreans kept some of these prisoners, known as P-O-W-s, which stands for "Prisoners Of War." This means they were not allowed to leave North Korea and go back to their home countries.
The North Koreans kept them in camps and made them work really hard, which was not fair. Many of these prisoners tried to escape, but it was really hard and dangerous. Some of them were able to escape, but many were not.
It's now many years later, and some of these P-O-W-s are still in North Korea. Their families miss them very much and want them to come back home, but the North Korean government won't let them go. It's a very sad situation.