The following version of the book was used to create this study guide: Harkness, Deborah. Shadow of Night (Book Two of the All Souls Trilogy) Penguin Group, New York, New York, 2013. Kindle AZW file.

In Shadow of Night, the second installment of the All Souls Trilogy by Deborah Harkness, Diana Bishop is a witch married to Matthew Clairmont, a centuries-old vampire. Despite rules against inter-creature relationships, the two are certain they are supposed to be together. However, they have two significant problems. The first problem is that creatures (vampires, witches, and daemons) are dying out in the 21st Century. Matthew and Diana believe the answer could lie in a mysterious book known to them as Ashmole 782. Diana, a student of alchemy who has resolutely refused to learn magic, retrieves the book at a library. She discovers it is “broken” with words scrambling all over the pages and three pages missing altogether. After Diana is the first to get the book, other creatures immediately hone in on her power. This leads to a second problem because Diana has never learned to use or control her magic. Now that she is being pursued, she does not have time to learn.

As a student of history, Diana expects to step directly into society during the 1500s. Matthew already lived through the 1590s and expects that he will simply go about his business there while he and Diana search for a teacher and the manuscript. Both are wrong. They spend the first weeks of their time here without accomplishing anything. Diana recognizes the names of many of Matthew's friends, including Sit Walter Raleigh, Christopher Marlowe, Henry Percy, and Thomas Harriot. She makes discoveries about Matthew as well, including that he is a member of the famous group she knows as the School of Night and a member of the Congregation (a board that governs creatures and sets rules, such as the one forbidding Matthew and Diana's marriage). When Matthew is summoned to his family home at Sept-Tours, Diana gets to meet Matthew's vampire father, Philippe, who initially refuses to acknowledge the marriage or guarantee Diana's safety. After getting to know Diana and seeing the strength of her relationship with Matthew, Philippe relents and claims Diana as a member of his family. Later, Diana encounters her father, Stephen, who has the power to time travel. Diana relishes the time she gets to spend with her father, though it is over much too soon. Stephen warns Diana and Matthew that they have become complacent in their actions and are changing the past with their interactions.

Diana and Matthew meet with Queen Elizabeth's astronomer, Dr. Dee, in the hope he has the Ashmole 782. They discover his assistant, Edward Kelley, stole the manuscript and now resides in Prague. Queen Elizabeth gives them permission to travel there because she fears Edward will create the famed philosopher's stone and hand it over to Emperor Rudolf II. Matthew and Diana manage to retrieve the manuscript. But, it is after Edward tears out three pages. The book is made of human skin, hair, blood, and bones. Matthew and Diana sense the dark magic around it. They learn they cannot take it back to present time with them. The book remains a mystery.

Diana becomes pregnant, a phenomenon that most believe cannot happen because Matthew is a vampire. She loses the first child, and the couple struggles through grief. Diana locates a group of witches willing to help her. Led by an elder named Goody Alsop, Diana learns that she is a weaver – a witch who is able to write spells rather than just learning the spells handed down through covens and families. She also learns that she has a familiar, a firedrake named Corra. Diana is terrified of losing control until one night when Stephen urges her to take a more casual approach to her magic. Diana begins to change from that point, and she is confident when she and Matthew make plans to return home. By this time, Diana is again pregnant. She discovers she is carrying twins. They arrive in the 21st Century at Diana's childhood home and travel back to Sept-Tours where members of both their families wait, ready to protect Diana and the babies and to face whatever lies ahead for the creatures.