Lady Midnight

by Cassandra Clare

Emma Carstairs has been living with the Blackthorn family: her parabatai, Julian; his siblings Livvy, Ty, Dru, and Tavvy; and their uncle, Arthur, in the Los Angeles Institute since her parents' deaths during the Dark War five years ago. Having grown into a prodigious Shadowhunter, she is still investigating the true cause of her parents' demise, despite the Clave telling her that they were killed by the late Sebastian Morgenstern. According to Johnny Rook, a mundane shopkeeper from the Shadow Market, similar murders befell eleven faeries, whose kind are ostracized by the Clave under the Cold Peace for their support of the Endarkened. Later, Emma also investigates a mundane murdered apparently by the same culprit who killed the faeries. Ty's research points to the victims being killed inside sacred locations known as the ley lines as part of a dark ritual.

Meanwhile, Julian struggles between running the Institute, since Arthur is functionally insane by his previous experiences in Faerie, and his love for Emma, despite parabatai being forbidden from pursuing a romantic relationship. He gets the medication for Arthur's illness from Malcolm Fade, the High Warlock of Los Angeles. Diana Wrayburn occasionally helps the younger Shadowhunters with the upkeep of the Institute, but refuses to replace Arthur as leader and frequently leaves for other missions.

One day, the Wild Hunt, a group of traveling faeries led by Gwyn ap Nudd, arrive to deliver Mark, the eldest Blackthorn brother, kidnapped by them during the Dark War. They demand that the Shadowhunters solve the faeries' murders—secretly, because of the Cold Peace—or else they will take Mark back. Changed by his time in Faerie, Mark finds solace only in Cristina Rosales, a Shadowhunter from the Mexico City Institute currently staying in Los Angeles. With Mark's help, Emma finds a cave which serves as a convergence point for the ley lines, managing to take evidences before being attacked by demons. Ty's research about the mundane victim points them to the victim's girlfriend, who has committed suicide in her house. Taking an invitation to the "Lottery", Emma and Julian are attacked by demons and the latter is gravely injured. Despite this, Emma manages to heal him quickly.

Ty and Livvy translate the evidences from the cave and are puzzled to find that they are passages from "Annabel Lee", the last poem by Edgar Allan Poe. Meanwhile, Emma, Julian, Mark, and Cristina attend the Lottery and see that it is held by a cult whose members kill to achieve luck. Emma and Julian question Rook further, learning the place where Casper Sterling, the latest winner of the Lottery, currently lives and that the Lottery's participants are followers of the mysterious Guardian, before being shooed away when they and Ty meet his son, Kit. Emma goes back to the cave and finds a portal which transports her to the sea. Julian, through his parabatai bond, rescues her. They subsequently admit their love for each.

Eventually, Ty completely translates the runes carved onto the victims' bodies and learns that the ritual, which requires thirteen sacrifices, also demands a Blackthorn blood. Emma and Cristina race to capture Sterling, but are too late to stop him from murdering the thirteenth victim, a witch. Sterling himself is murdered by the Followers, his hand cut and taken. The two unexpectedly meet with Diego Rosales, Cristina's ex-boyfriend and the reason why she left Mexico City. Diego is a Centurion—graduates of Scholomanche—and claims that he was sent to investigate the Guardian's ritual, whose goal is to resurrect someone. Back home, the Blackthorns connect the ritual to an old Shadowhunter folktale, "Lady Midnight". In the story, a woman was killed by her parents and her lover made a deal with the Faerie king to conduct a ritual which required Blackthorn blood and the Black Volume of the Dead.

Meanwhile, Mark is visited several times by his boyfriend from the Wild Hunt, the Unseelie prince Kieran. Kieran becomes jealous of Mark's growing relationship with Cristina. When Kieran overhears Mark telling her Gwyn's weakness, he reports this to Gwyn, who comes alongside Iarlath, the right-hand man of the Unseelie King, to punish Mark by flagellation. Julian initially volunteers, but Emma, unable to see him being tortured, volunteers herself and is badly injured. This causes Mark to reject going back to the Wild Hunt and accept being a Shadowhunter.

Eventually, the Blackthorns research their family history and find out that "Lady Midnight" is based on the story of Annabel Blackthorn, a Shadowhunter who fell in love with a warlock. Emma calls Rook, the latter admitting that he worked with the Guardian to trick the Lottery winners. By piecing together the clues, she realizes that Malcolm is the Guardian. However, before they can act, Malcolm has tricked Dru to give Tavvy to him. Kieran visits the Institute and, in goodwill, reveals two information: Iarlath is working with Malcolm, and Emma's parents were killed to test the resurrection spell. The group and Kieran go to the cave. Confronting Malcolm, he threatens to reveal Diana's secret before knocking her out. The younger Shadowhunters fight Malcolm and Emma manages to steal the Hand of Glory, which contains the hands of the Lottery winners. Upon being cornered, Emma opens the cave portal, sending Malcolm to be eaten by sea demons.

The Shadowhunters head back home and are greeted by Clary Fairchild, Jace Herondale, and Inquisitor Lightwood, fresh from attending Simon Lovelace's and Isabelle Lightwood's engagement party. The three agree to let Mark stay at Los Angeles. Meanwhile, with Malcolm's death, Rook loses the protection on his house and is immediately killed by demons. Kit is rescued by Tessa Gray and Jem Carstairs and told that he is a descendant of the Lost Herondale. The two then take him to the Los Angeles Institute. Approaching Jem, Emma is told that parabatai who are in love with each other have strengthened runes, but they will also bring misery to everyone around them. With this in mind, she breaks up with Julian and pretends to date Mark.

In the epilogue, Annabel Blackthorn opens her eyes.