Okay, so there was a family in Spain called the Álvarez family. They had a mom and dad, and two kids - a boy and a girl.
Now, normally, people don't marry or have babies with their family members, like their siblings. That's called incest, and it's against the law in most places.
But in this case, the brother and sister in the Álvarez family fell in love with each other and decided to have a relationship. They even had a baby together.
The police found out about this and arrested them, because it's against the law. They went to court, where they were found guilty of committing incest.
Even though they loved each other, they had to be punished by the law because what they did was wrong. It's important to remember that we shouldn't do things that are illegal or harmful to ourselves or others, even if we feel like they're okay.