The gold of her ruined wedding dress gleamed in the witchlight as she spun away from the Demon. It screamed in annoyance, an ugly, ear-piercing wail which reverberated right through her bones. Jem lay sprawled against the alter, unconscious, his silver hair plastered to his face with blood. The Demon reared up on its hind legs, black ichor dripping from the long gash Will had just made in its side. "Will!" She screamed. He whipped his head around in her direction, a gleaming seraph blade in hand, just as the Demon struck out with a taloned arm. The blow hit her full force across the chest, sending her flying into one of the Church pillars with a sickening crunch. A wave of darkness crossed over her vision and the sounds around her dimmed to a jumbled hum.
"Tessa!" Will called her name, slashing out at the demon with his seraph blade, severing the mutated creature clean in half. She saw Will running towards her just before her eyes closed, a wave of clockwork creatures and demons surging behind him; an insectile demon approaching the alter,
"Jem," she whispered, before the darkness took over.
Tessa slowly regained consciousness, her angel fluttering nervously against her neck. "Tess, Tessa! Wake up, please," Will had her by the shoulders, shaking her, his face plastered with worry.
"Will...Jem, is he...?" She tried sitting up, but a striking pain shot through her head.
"Tess there's no time, you have to go, the Magister will be here any minute. Magnus will portal you back to the Institute, and we-"
"No! I'm not leaving you! Jem! Will, the Demon, where..?" She clutched at his arm, desperately searching for Jem's limp form, but he was no longer at the altar.
"Tess, just go! The Magister is coming... Magnus, take her..." Only then did Tessa notice the Warlock standing behind him, blue flames sparking off the tips of his fingers. Magnus hauled her to her feet and started towards a shimmering sliver of air, the Portal, Tessa thought. Ichor and metalwork scattered the floor, mingled with the blood of Shadowhunters. What remaining wedding guests there were darted around the Cathedral, Seraph blades and other angelic weaponry gleaming in hand; but for every clockwork creature or demon that was cut down, three times as many Shadowhunters were defeated. Magnus tugged on her arm, pulling her towards the Portal, but a familiar flash of silver had caught her eye.
"Jem!" he was across the Cathedral, his face pale and covered with a sheen of sweat and blood. The Magister had his arm slung around his neck in a headlock, a sickening grin on his face. Leaning in towards Jem's face, he whispered into his ear, eyes never leaving Tessa's face. Jem's silver eyes widened in fear, locking onto Tessa's.
"No..." he mouthed. Tessa tried to wrench free from Magnus' grasp, but he was too strong. The last thing she saw before being pulled into the Portal was the Magister letting go of Jem, and him crashing to the floor.