Josephine Delamarre is a guardian angel that Heaven sends to earth. With her psychological insight, ability of persuasion and magical powers, she manages to help people who have problems. She appears at the beginning of each mission; when the mission is completed, she disappears with a click of her fingers.

The Section de recherches is a special unit of the Gendarmerie nationale, responsible for the most complex cases. In Bordeaux (from 2006 to 2013) and then in Nice (since 2014), child abductions, disappearances, heinous or sexual crimes are the daily lot of the investigators in this research unit. In the search for witnesses, the team is authorised to extend its investigations beyond France's borders.

The story revolves around the people of Sète, France. Their lives are punctuated by family rivalries, romance and scenes from daily life, but also by plots involving police investigations, secrets and betrayals.

Following the inexplicable sinking of a trawler and its fishermen who remain untraceable, Abigail, an oceanographer, is sent by IFREMER on a mission to Fécamp, her hometown, which she left a few years earlier following a family tragedy.