Alternate Ending of City of Heavenly Fire. Contains spoilers.

Part 2

"The walls are closing in," Magnus said.

Alec tried to pull Magnus farther upright; the warlock slumped heavily against him, his head almost on Alec's shoulder. Alec had absolutely no idea where they were going- he had lost track of the twisting corridors what felt like ages ago, but he had no desire to communicate that to Magnus. Magnus seemed to be doing badly enough as it was- his breathing ragged and shallow, his heartbeat rapid. And now this.

"Everything's fine," Alec soothed, his arm sliding around Magnus's waist. "We just have to make it to-"

"Alec," Magnus said again, his voice surprisingly firm. "I am not hallucinating. The walls are moving."

Alec stared-and felt a flutter of panic. The corridor was heavy with dusty air; the walls seemed to shimmer and tremble. The floor warped as the walls began to slide toward each other, the corridor narrowing from one end like a trash compactor slamming closed. Magnus slipped and hit one of the buckling walls with a hiss of pain. Panicked, Alec seized his arm and pulled Magnus toward him.

"Sebastian," Magnus gasped as Alec began to drag him down the hall, away from the collapsing stone. "He's doing this."

Alec managed an incredulous look. "How would that even be possible? He doesn't control everything!"

"If Lilith and Asmodeus have given him enough power here," Magnus said as he took a rattling breath and pushed himself into a run, "he could control this whole world."

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Isabelle shrieked as the ground opened up behind her; she threw herself forward just in time to avoid toppling into the chasm that was splitting the corridor apart. "Isabelle!" Simon shouted, and reached to catch her by the shoulders. He wrenched Isabelle up with such force that they both toppled backward and Izzy landed on top of him.

Isabelle sprang to her feet, pulling him up after. They had lost Luke and Jocelyn back in one of the other corridors as a wall split apart, shedding mortarless rocks like scales. Everything since then had been a mad dash, dodging splintering wood and falling stones, and now chasms opening up in the ground. Simon was fighting despair- he couldn't help but feel that this was the end; the fortress would fall apart around them, and they would die and be buried here.

"Don't," Isabelle said, breathless. Her dark hair was full of dust, her face bloody where flying rock had cut her skin.

"Don't what?" The ground heaved, and Simon half-ducked, half-fell forward into another corridor. He couldn't rid himself of the thought that somehow that fortress was herding them. There seemed a purpose to its dissolution, as if it were directing them somehow...

"Don't give up," she gasped, flinging herself against a set of doors as the corridor behind them began to crumble, the doors swung open, and she and Simon tumbled into the next room. Isabelle sucked in a gasp, quickly cut off as the doors slammed behind them, shutting away the explosive noise of the keep. For a moment Simon simply thanked God that the ground under his feet was steady and the walls weren't moving.

Then he registered where he was, and his relief vanished.

"Simon! Isabelle!" Clary shouted, relief flooding over her. Atleast they were still alive, and here. They ran over to where Clary and Jace were standing, and stood, poised ready for battle. The Endarkened ones remained where they were, and Sebastian smiled.

"Nice of you to join us. Your friends will be here soon, and then you can all die together." he said with a lot of confidence in his voice.

Clary opened her mouth to reply, but before she could say anything, the entryway to the room burst open and Magnus and Alec spilled in, followed by Luke and Jocelyn. The doors slammed behind them, and Sebastian clapped his hands together. Luke and Jocelyn helped Alec and Magnus up, before scrambling to join the others.

Sebastian's face lit up with a stomach-churning grin. "Now everyone's here," he declared, his voice delighted. "It's time to party!"