The film is inspired by Karina participation at the Eurovision Song Contest 1971 and shows actual footage of her performance there.

At the same time, Juanito has discovered a teen music group called La Pandilla, whom he takes to his house and hires Karina as a governess to educate them.

She teaches the children singing and over time she gains their affection and love, and the interest of Carlos.

Seeing that Carlos pays too much attention to Karina, Marta leaves for a rival record label.

The children convince Juanito and Carlos to let Karina be the one to represent Spain in Eurovision with "En un mundo nuevo".