Ok kiddo, do you know what "repatriation" means? It means sending someone back to their home country.
So, there is a special agreement between the countries in Europe called the "European Convention on the Repatriation of Minors." "Minors" are people who are younger than 18 years old.
This agreement is for when a minor is taken or kept in another country without their parent's permission. It happens sometimes when parents are separated, divorced or have different nationalities.
The Convention says that the country where the minor has been taken without permission must give them back to the country they were living in before. And they have to do it as quickly as possible, so the minor can go back to their normal life with their family and friends.
This Convention is very important because it helps to protect the rights of children and to make sure they are safe and with their families.