Barbara Carey flies to Italy to visit her blind sister Mary Ann, who is studying in a music academy. Once in Rome Barbara discovers her sister has disappeared and, according to the Italian police, she may have been murdered by a maniac who is obsessed with young sightless women. With the help of Martin Foster, from the British Embassy, Barbara starts trying to find out what happened to Mary Ann. She even pretends to be blind herself in an attempt to attract the killer, and finally the clues lead her to Seagull Island, privately owned by a mysterious British citizen named David Malcolm. Barbara must then find the answers to several questions: was Mary Ann really kidnapped? What happened to David's wife and son in the island? And why is David's relative Carol so unhappy to see a woman with him?

Inspired by the original novella by Robert Louis Stevenson, Jekyll and Hyde is set in 1930s London and follows Robert Jekyll, the grandson of Henry Jekyll, on his quest to discover his real identity, his true family history and the nature of his ‘curse’ – which his foster father, Dr Vishal Najaran, is controlling with medication. His journey takes him into a dark and unforgiving place, as his alter ego seems capable of anything. At the same time there are shadowy forces trying to find Jekyll and the source of his powers.

Jeanne Deber, known as "La Mante", the famous serial murderer who terrorized France more than 20 years ago, is forced by the police to come out of isolation to track down her copycat. She agrees to collaborate on one condition: to have only one interlocutor, Damien Carrot, her son, who became a cop because of the crimes of his mother, and who refuses all contact with her since her arrest.