The film presents the five members of the popular music group La Pandilla in a tangled comedy-musical plot, involving a stolen audio recording, during the summer of their group tour. Includes sequences within the same concerts, where the enthusiastic public is also shown. The plot is woven around this tour, alternating performances with funny incidents at a hotel in Condado where they stayed.

Filmed at the Hotel El Conquistador in Fajardo, Puerto Rico, the film presents the musical group La Pandilla in a plot based on espionage.

Karina arrives to a mansion to work as a governess of a group of singing children. She must take care of their education, and she decides to use music to teach them. Meanwhile, the record company where the children work is busy with another project. Their biggest star, Marta, is getting ready a song to represent Spain in the Eurovision Song Contest 1971. Carlos, the composer of the song, titled "En un mundo nuevo" ("In a new world") meets Karina in the mansion and starts feeling affection to the girl, something Marta, who is Carlos' girlfriend doesn't like at all. She is also jealous of Karina for her musical abilities, and when one day Marta catches Karina with Carlos singing a song composed for the governess, she gives him an ultimatum, if Karina doesn't leave the mansion at once, she will break her contract with the record company and won't sing "En un mundo nuevo" in the Eurovision Song Contest...