Gregorian chant is beautiful and mysterious. It’s music that surpasses us, penetrates us, transports us to a distant past. And yet it can be heard much more widely today than we might imagine.

It is not only heard in churches or within the cloistered walls of monasteries, but also in recording studios, pop concerts, choirs and even used by the world’s greatest voice coaches.

Why? How has Gregorian chant passed through the membrane of time? What does it give us that other vocal techniques do not? Why is there so much "popular" enthusiasm for this form of sacred song, which has long had a reputation for being complex?

Seeking answers to these questions, we set out on a journey in which the process of transmission is illustrated in a concrete fashion by the musicians, singers, teachers, young apprentices and erudite connoisseurs who use Gregorian chant on a daily basis.

Building a bridge between the Middle Ages and the pop age, the documentary also shows us how great orators, whether priests or rock stars, have adopted this art in order to achieve excellence. We will also find out that a tradition is never set in stone, and that it can be enriched by new popular practices.

The film is shot in Metz, the cradle of Gregorian chant, and some of the many other unexpected places in which this music, born in France in the Middle Ages, can be heard today.