City of Glass is the third installment in the six-book Mortal Instruments series, following City of Ashes and preceding City of Fallen Angels. In City of Bones (the first installment), Clary (raised as a human—or “mundane”—by her Shadowhunter mother, Jocelyn, and her werewolf father figure, Luke Graymark) is introduced to the Shadowhunter world when her mother is kidnapped by her biological father, Valentine. Her mother uses a potion to put herself into an enchanted sleep to prevent Valentine from torturing information out of her. Clare uses the sleep potion as a plot device in both City of Ashes and City of Glass. Clary and fellow Shadowhunter Jace are attracted to one another from the moment they meet, which becomes complicated when they learn that they are siblings at the end of City of Bones. Ultimately, this turns out not to be true, but they grapple with their feelings throughout the second and third books until the truth is revealed toward the end of City of Glass. Sebastian (the real Jonathan) is Clary’s actual brother, and City of Glass sets him up as the main antagonist for the second half of the series.