Okay kiddo, a long time ago in ancient Rome, there were two big groups of people - the patricians who were rich and powerful, and the plebeians who were not as rich or powerful. But over time, the plebeians started to get upset because they weren't being treated fairly, so they created something called the plebeian council.
This council was a group made up of only plebeians, and they were in charge of making important decisions that affected their group. They could pass laws and make decisions about things like taxes and how the government should be run.
Now, there was still another group of people - the patricians - who had a lot of power and they didn't want the plebeian council to have too much power. But the plebeians were determined to have a say in how their group was being treated, so they fought for their rights and eventually won more representation in the government.
So, to sum it up, the plebeian council was a group of common people who came together to have a say in how they were being treated by the government in ancient Rome. They fought for their rights and eventually gained more power and representation in the government.