The German author Jörg Bong (born in 1966 in Bonn/Bad Godesberg) lives between his country and the French region of Brittany. This is the fifth book in a series featuring Commissioner Georges Dupin as the protagonist.

At the edges of Brittany, amidst the elemental forces of the Atlantic, lies the island of Ouessant, with its wild beauty and intense greenery. There, Inspector Dupin is given a special assignment by the prefect to solve a mysterious death. A penniless Celtic musician is found dead on the shore shortly before the most important festival of the year. The police discover a clue in his house related to an ancient dark ritual.

However, the tightly knit community of the remote island hinders Dupin’s investigation: sirens, priestesses, and storytellers live here outside the rules and know what they are doing—what counts is the invisible. Dupin takes on the almost impossible task of figuring out what it could be.

The author maintains his style of emphasizing the description of the landscape and the cultural traditions of Brittany, in this case the ancient Celtic culture and its rites. Christian culture remains in the background: the narrative mentions a church and the parish priest, but God or spiritual life do not appear.

From a moral perspective, the characters pursue their own interests while respecting loyalty to the small group in which they move. Some are driven by greed. The island’s society is dominated by women, and marriage does not matter. There are no inappropriate descriptions.