Okay kiddo, so imagine you have a really special toy that you love very much. You took it to the park to play with it, but then you left it there by accident. Now you really want it back, but you don't know where it is or who took it.
In grown-up world, sometimes people break the rules and do bad things, like stealing or hurting someone. If they did something really bad in one country, they might try to run away to another country to hide from the police. But that doesn't mean they shouldn't have to face the consequences for what they did.
That's where the European Arrest Warrant comes in. It's like a special tool that allows police in one country (let's say France) to ask police in another country (let's say Spain) to arrest someone who did something bad in France and ran away to Spain to hide.
But it's not just any kind of arrest warrant - it's a special one that makes it much easier and faster for the police to catch the bad guy. The police in France don't have to go all the way to Spain to catch the bad guy themselves. Instead, they can just ask the police in Spain to do it for them.
And the police in Spain have to do it, because all the countries in the European Union agreed to this special rule. So if someone did something bad in France and ran away to Spain, they wouldn't be safe anymore because the police in Spain would have to catch them and send them back to France to face trial.
And just like how you really want your special toy back, the police in France really want the bad guy to face justice for what they did. So the European Arrest Warrant lets them work together with the police in other countries to make sure everyone is following the rules and behaving nicely.