Tessa Gray crossed the Atlantic to join her brother in England. Instead of her brother Nathaniel, she's met and kidnapped by the Dark Sisters. They torture her into learning how to use her shape-shifting power, using her brother as bait. She learns their plan of preparing her for someone named the Magister, who plans on marrying her.
Before she can save herself, Tessa is rescued by William, a Shadowhunter. Shadowhunters hunt down the Downworlders who harm humans. Tessa is taken to the London Institute where she learns the Downworlders are beings like vampires, demons, and warlocks who thrive on certain humans--her brother being one of those humans. Tessa is determined to find her brother and rescue him, hopefully with the Shadowhunters' help.
As details unravel and the enemy becomes clear, Tessa may be making some hard decisions.
The first in a new trilogy, I couldn't put it down. This is a prequel series to Clare's Mortal Instruments series, which I haven't read yet. The story is well-written, characters fleshed out, and the plot is exciting. Lots of vivid action, setting, and plot to keep anyone happy. It is more in historical fiction, but that shouldn't stop anyone from picking up this great story.