It was time for regime change in Iran. It seems that regimes change as much as changes judges.
People are excited, but her parents know best that any peace can be expected.
She bullies a child in school because her father was in the Shah's secret police and killed many people.
Her mother clarifies to her: "Her father did it, but it is not Ramin's fault", after this she realizes that she has to learn to forgive.
My opinion:
I think that their happiness is explicable because they feel free and without fear, the girl must learn to forgive since in most situations it is necessary to do so.
