This is a sequel to Clockwork Angel, which happens to be a prequel series to The Mortal Instruments series. I haven't read any of The Mortal Instruments series and the books still make sense, but you definitely want to read Clockwork Angel before this one. Tessa lives in Victorian London. She moved there from the United States, because her brother Nate asked her to after her Aunt Harriet died. Unfortunately, Nate only wanted her to come to London because The Magister wanted to marry her and use Tessa's power that she didn't even know she had for himself. Tessa was rescued by the Shadowhunters, who she still lives with at the start of this book. But there's a possibility that the safety that Tessa has found with the Shadowhunters could be taken away. Charlotte, the director of the Institute, is being threatened. Certain Shadowhunters no longer want her to be director. It's up to Tessa, Will, and Jem to figure out just why they want Charlotte gone and ultimately to find The Magister, before he comes after Tessa again. This book was full of great action and adventure. Not to mention one of my most favorite times and places. Victorian London is an amazing place, full of mystery and magic. I enjoyed the plot, although I thought the language could be improved.