There is a special magic in singing together - everyone who has ever sung in a choir agrees on that. When a wide variety of voices come together in all their diversity, an enormous musical power emerges. OUR HEARTS - ONE SOUND follows this magic and accompanies two choir directors and one choir director as they turn a group of singing enthusiasts, some of whom could not be more different, into choirs of rousing musical intensity. It is a glimpse into a field of work in which closeness and distance, identification and projection have to be brought into balance anew each time. Sometimes playful, sometimes serious, but always highly fascinated and open-hearted, the documentary illuminates choral singing as a unique symbiotic connection between all participants. The overwhelming feeling of being part of a whole determines the rhythm of the film. Humanity is discovered in music, where the shared experience of sound becomes both a social adventure and a moment of self-realization.