Seodaemun prison was a place where people who broke the law in South Korea were sent to stay as punishment. It was a very old prison that was built a long time ago and was used by the government to keep people who did bad things away from the rest of society.
Inside the prison, there were many small cells where the prisoners had to sleep and eat. The cells were very small, and the prisoners didn't have much space to move around. Sometimes, the prison guards would treat the prisoners badly and not give them enough food or water. This was very unfair and made the prisoners feel sad and hopeless.
Some people were sent to Seodaemun prison because they did things the government didn't like, even if they weren't really breaking the law. These people were often treated worse than the actual criminals because the government wanted to make an example out of them.
Many people were very unhappy about Seodaemun prison and thought that it was very unfair. Eventually, the government closed the prison down, but it is still remembered as a place where many people suffered unfairly.