Diana and Matthew are now guests of Ysabeau De Clairmont, an ancient vampire and killer of witches, at the family's ancestral home, Sept Tours in France. Ysabeau warns Matthew that his love for Diana puts his entire family in danger. Knox is now back at The Congregation and calls an emergency meeting to discuss Matthew's liaison with Diana, as it violates the rule sanctioning relationships amongst species. This puts Baldwin, Matthew's brother and head vampire at The Congregation, on the spot. Later, Domenico, a vampire sent on behalf of The Congregation, turns up unannounced in France to demand Diana's immediate return, and Matthew receives a call that his research lab has been broken into. Fearing Ysabeau was right with her warning, Matthew resolves to abide by the Congregation rules and leaves for Oxford, just as Ysabeau begins to realise how powerful Diana really is.

Matthew crosses a dangerous line when he returns to Oxford. Diana discovers his dark past, before something unexpected tears them apart.

Matthew and his team soon realise Diana's fate and start a desperate search to find her. At La Pierre, Satu conducts a dangerous spell to try to discover the secrets of Diana's magic: it is a terrifying ordeal for the young witch and nearly kills her. Thanks to Em's scrying, Matthew discovers Diana's location and the race is suddenly on to rescue her. Trapped inside a well, Diana is finally able to harness her powers to her own will and flies out of the dungeon before being airlifted to safety by Matthew and Baldwin. Back at Sept Tours, Diana is tended to by Matthew, Ysabeau and Marthe, who discover Satu has left a horrific scar on her. The imprisoned Satu uses magic borrowed from Meridiana, an ancient witch, to free herself,and take Meridiana with her. As enemies begin to appear on several fronts, Matthew calls for Baldwin and the Knights of Lazarus to protect Diana.

Diana and Matthew travel to Madison, and the safety of her American childhood home. Meanwhile, an exhausted Satu roams the French countryside and discovers the secret of Meridiana's prophecy. In Venice, Baldwin struggles to retain control of The Congregation after his failure to bring Diana back to them. Later, Diana discovers the truth as to why she's unreliable and unpredictable around magic: she was spellbound. Now she must come to terms with her abilities and embrace them. Whilst she does so, Matthew enlists the help of Marcus and Miriam to help protect her. Back in Venice, Juliette finds an opportunity to finally escape from her father-figure Gerbert and then seeks out her true love, Matthew, while Domenico capture Satu. As Diana's training goes from strength to strength, things take a dramatic turn when Juliette tracks down Matthew.

With danger at every turn, Diana and Matthew are forced to run. But will they escape in time? The Sky original production concludes.

Matthew and Diana head to Elizabethan London to find a teacher to harness Diana's powers.

As she continues her search for a mentor, Diana meets wealthy alchemist Mary Sidney. London's vampire ruler demands fealty from Diana and Matthew.

In the present day, Domenico makes a disturbing discovery in Oxford. Back in 1590, Matthew is forced to beg for forgiveness from Father Hubbard.

Another vicious vampire murder rocks present-day Oxford. Marcus makes a breakthrough in his search for Diana and Matthew's journey back in time.

Matthew and Diana arrive in France on their journey to face Philippe, while Louisa and Kit cut a swathe through London.

Philippe makes a troubling discovery, provoking a conflict with Matthew. In the present, Ysabeau, Em and Sarah start to look for a message.