Reluctant witch Diana Bishop and vampire Matthew Clairmont seek refuge in the fascinating and treacherous world of Elizabethan London. There, they must find a powerful witch to help Diana control her magic and search for the elusive Book of Life.

As she continues her search for a mentor, Diana meets wealthy alchemist Mary Sidney. London's vampire ruler demands fealty from Diana and Matthew as he is unnerved by their sudden arrival in the City.