Okay kiddo, let me explain the Dirty War in Mexico in a way that will make sense to you.
The Dirty War in Mexico was a time when the government was trying to control people who were speaking out against them. You know how sometimes you get in trouble for saying something your parents don't want to hear? Well, it was like that but on a bigger scale.
The government didn't like it when people spoke out against them or protested the things they were doing. So they decided to do really bad things to those people to scare them into being quiet.
They would take people away in the middle of the night and no one would ever see them again. They would be tortured, and sometimes killed. It was really scary for the people who were being taken away, and also for their families who didn't know where they were or if they were alive.
The government thought that by doing this, they would be able to control the people and make them stop protesting. But it didn't work. People kept speaking out and protesting, and eventually, the government had to stop doing the bad things and start listening to what people had to say.
So that's what the Dirty War was in Mexico. It was a scary time when the government tried to control people by doing bad things to them, but in the end, the people won and were able to speak out and protest without fear.