“I know,” Lizzie said. Her voice came out as a whisper. She cleared her throat. “Johnny,” she said. “Johnny, this is the flight of stairs where Amelia died.”

Johnny was staring down into the shadows of the stairwell below. “Just a little step back in time,” he said, almost to himself.

“No!” Lizzie said. Her head was buzzing with dark shapes and patterns. She wanted to run away. “Johnny, you can’t bring Amelia back,” she said. “I understand what you’re trying to do, but time doesn’t work like that. It can’t.”

“I’ve got to save Amelia,” Johnny said, as though he hadn’t heard her. “I couldn’t save Amy. She wouldn’t listen. You have to help me.” He turned to Lizzie and the suddenness, the urgency, made her draw back. He looked heartbreakingly young and hopeful. “I knew you would work it all out,” he said. “I knew you were different. I need you to call up the memories in the stone like you did at Baynard’s Castle. Then I can cross time.”

“No,” Lizzie said. “I won’t do it.” She tried to back away from the top of the steps but the swarm of dark shadows in her mind was clamouring for attention. There was something here that was too powerful for her to contain and it was terrifying. It was so strong that it dominated everything, filling all the spaces in her head. She fought to hold on to her own thoughts so that she would not be completely subsumed. Dizzily she put out a hand to steady herself against the wall only realising when the touch of the cold plaster seemed to burn her palm that it was the last thing she should have done. The memories in the stone had been set free.

The images were coming thick and fast now, like a jerky silent film, the figures jostling on the screen. Lizzie couldn’t breathe. She was drowning in sorrow. Her lungs were full of it. She could taste it in her mouth. Images spun through her mind, animated with sound as well as movement now.

“It’s not Amy,” she said. “It’s not Amy whose grief we can feel here. Amy had hopes and plans. She was excited, happy. She was going to escape and start anew...” She took a deep breath. “There’s someone else here,” she said. “Amy calls her Anna. It’s Anna whose grief we can sense, Anna who is broken with guilt. She never meant for it to happen. She did not want Amy to fall. It was an accident—”

The images shifted abruptly and Lizzie saw not Amy Robsart but Amelia, in one of her long, flowing dresses, her blonde hair loose about her shoulders, standing at the top of the stone stair, suitcases scattered about her. She was looking back at someone and she was smiling, but it wasn’t a warm smile, it was edged with impatience and spite. Lizzie could feel Amelia’s emotions, the irritation and the exasperation. Amelia wanted to get away and someone was calling her back...