"Sur les pas de la main noire" or "La Main noire" : what is it about?

Normandy, august 2006 :  an unexploded World War II  shell  detonates in a courtyard, and  a black  hand enters   aristocratic born  singer Luna’s bedroom, like a  hideous soft spider which oozes black inky oil. Whose hand is it ? In his seventh novel, Robert Vincent invites you to travel from the past to the present in a  detective story brimming with suspense and dark humour.  « In the wake of the black  hand» :  Prose that is raw and tense yet filled with poetry and melody.

Thanks to Margaret C. for helping.