Sarah Heap looked much smaller than Simon remembered. In fact, when the Things that had gone to fetch her came back into the entrance hall, Simon could see no sign of Sarah. For a brief moment of hope he thought his mother was not there after all. But as they drew near, Simon saw Sarah's faded yellow curls just visible inside the press of Things that surrounded her.

Murmuring in the excited way that Things have when they know something unpleasant is going to happen to someone, they pushed and poked the terrified Sarah Heap toward Simon. Sarah stared at Simon in horror, and on her face Simon read what he had been so afraid he would see - his mother thought that this was his doing.

"Mum, Mum, please, I didn't do this. I didn't!" said Simon, instantly back to being a little boy wrongly accused of something.

Sarah clearly did not believe him. "Oh, Simon," she sighed.

But the next few seconds made Sarah change her mind.

"You will open the door now," the strangler-Thing intoned.

"N-no," stuttered Simon.

"You will," the Thing informed him. It shoved a smaller Thing standing beside Sarah out of the way, then it raised its bony hands and placed them around Sarah's neck, which looked, Simon thought, so very thin and fragile.

"Simon," whispered Sarah. "What do they want?"

"They want to get out, Mum. But they can't. They want me to do it for them."

"Out into the Castle?" Sarah looked horrified. "All of them? Out there? With all those poor people?"

"Yes, Mum."

Sarah looked outraged. "No son of mine will do that, Simon."

"But Mum, if I don't . . ."

"Don't!" said Sarah fiercely. She closed her eyes.

The Thing tightened its fingers around Sarah's neck. Sarah began to choke.

"No!" yelled Simon. He sprung forward to wrench the Thing from his mother but the four other Things pounced on him and held him fast. "Stop it, stop it, please!" Simon yelled.

"When you open the door, I shall stop," replied the Thing, pressing into her throat with its thumbs.

Sarah's hands clawed uselessly at the Thing and gasping sounds came from her throat as she struggled for air.

Simon was in despair. "No . . . please stop."

The Thing's blank eyes stared back at Simon. "Open . . . the . . . door," it commanded.

Desperately Simon glanced around, looking for Sir Hereward for help. But the ghost had been pushed backwards by the throng of Things that had gathered for a better view, and all Simon could see was the tip of his sword waving uselessly in the air. He was on his own.

Sarah drew in a loud, rasping gasp and went limp.

Simon could stand it no more - he was killing his own mother. All he had to do was to open one stupid door and she would live. If he didn't, she would die. That one certainty overwhelmed him. Nothing else mattered. Everything else was in the future, but his mother was dying right now, before his eyes. Simon made a decision: everyone would have to take their chance; at least they would have a chance - unlike Sarah, who had none unless he gave in. He stepped up to the Palace doors and placed his hands on the thin film of Magyk that covered the ancient wood. And then, hating every moment of what he was doing, Simon Heap spoke the Reverse for the Quarantine.

The Thing dropped Sarah like a hot potato - humans were not pleasant objects for Things to touch. "Open it," it hissed at Simon.

Simon turned the huge brass door handle and pulled open the heavy double doors. The Things poured out of the Palace like a stream of dirty oil, but Simon paid them no attention - he was kneeling on the worn limestone flags, holding Sarah. She took in a long, wheezing breath, so long that Simon wondered if she would ever stop. Slowly the mottled blue of her face suffused with pink and Sarah's eyes flickered open. She looked up at her oldest son in confusion.

"Simon?" she croaked in a painfully hoarse whisper. She looked at him as if seeing him for the first time. "Simon?"

Gently Simon helped her sit up. A sudden gust of snow blew in through the open doors. Sarah was staring at him, remembering now. "Simon, you haven't?" she whispered. Simon glanced up at Sir Hereward, not daring to reply.

The ghost looked down at Simon sadly. There was nothing to say. He would have done the same for his own mother, he thought.

"Simon," said Sarah. "You didn't let them out. Did you? Oh no . . ."

Sarah sank back to the floor and Simon gently let her go. He sat beside her, head in his hands. He'd done wrong. He knew he had. But he'd had a choice only between two wrongs. And what choice was that?