Bad Wolf have published a summary of ADOW season 3 on their website:-
Beware Spoilers if you have not read the third book in the All Souls Trilogy –
A DISCOVERY OF WITCHES SEASON 3
A Discovery of Witches began when Diana Bishop laid her hands on Ashmole 782 and found herself thrust into a dark, sensual and thrilling world of creatures she had spent her life swerving.
The third season will close that circle and see Diana finally reassemble the Book of Life and crack open its tantalising mysteries. Matthew and Diana must find the Book and muster their forces to do battle with the greatest of their enemies: the allied members of the Congregation, who enforce the strict segregation of creatures.
Matthew and Diana’s first priority is the protection of their growing twins – two babies who represent threats to the entire foundation of the Congregation. Matthew has to face up to the consequences of his past, confront his own deep secret of bloodrage and make amends for some of his most violent acts in order to successfully launch his own family. Diana has to become a mother while facing the biggest challenge of her life – only she can unlock the mysteries of the Book of Life so that her children will not have to hide their true natures as Diana had to.
She must find the missing pages of the Book of Life and complete it, for it will be the only way that she can overcome the Congregation which dogs their steps at every turn: Powerful witch, Peter Knox, descends into madness hunting for the Book. Gerbert d’Aurillac seeks ultimate power within the Congregation and will stop at nothing to destroy the de Clermonts. Satu Jarvinen, Diana’s old enemy, is gearing up for the final confrontation. Meanwhile, Benjamin — a monster from Matthew’s past who has been lying in wait — will re-emerge to wreak his ultimate destruction.
Info from Bad Wolf website.
Thanks to adowtvcafe on Twitter for posting the link.