One of the earliest prog bands in Spain, Módulos knew how to mix their fresh and catchy Sixties style with more complex solutions coming from the British prog rock masters. This track comes from the album "Plenitud" and is a rather long song, including an instrumental first half, where different moments build up a lively and melodic piece of music, dreamy and colourful like a pop song, but also everchanging and unpredictable like a progressive track.
"Plenitud" was the third studio album by Módulos.
The final "Beatles-like" section, for example, comes in unexpectedly and acts like a cameo into such a diversified plot. But likely the main feature of "Promesas" is IMHO the sense of joy it conveys: the musicians actually enjoy their music and seem to celebrate their fully progressive search for a different horizon. Naive or not, this song is still fizzy and unaffected today as it was in 1972.