Who is behind the elusive name of "Temperance League"? And why is this killer raging against the wine producers of the villages along Lake Geneva shores? Daniel Cosandier, Chief Inspector of the Criminal Police of the Canton of Vaud tries to untangle the threads of this mystery, unexpectedly aided by a sociable, slightly mysterious elderly lady and her Portuguese friends. Inspector Cosandier, who has three great passions, his work, fishing and classic rock music, at the end of this hard investigation will realize that his life has become less solitary.