In search of an enchanted alchemical manuscript, Diana Bishop, an Oxford historian and heiress of witches, together with Matthew Clermont, a vampire, is transported from the 21st century to London in 1590, where she finds herself in the world of alchemy and magic and meets Matthew's old friends from the Mystic School nights. It is in old London that a witch must be found who will teach Diana to control her hereditary abilities, and Matthew is forced to confront his own past, which he thought was left behind. In addition, they find themselves drawn into a battle of supernatural forces that revolves around the mysterious Ashmole 782 manuscript.