The inhabitants of the windswept island of Sein, in the nineteenth century, in Brittany follow their own religion without need for clergy, but as strangers arrive, their faith and beliefs face a deep crisis.

A journalist who deals with the column "courier du cœur" has the absurd idea of ​​launching an investigation into the death of a pianist whom he claims to have been murdered. To dazzle his wife, a reporter for the newspaper, he disguises the facts in such a way that the police suspect him, then declare him guilty. It takes a number of adventures to get him out of this mess and get him back into his section.