"One traveler, at least," Petra hazarded. "I wonder what dimension he came from? And if he made it into our own world?
James noticed a series of symbols painted onto the hull of the ship, faded almost into obscurity. Among them was the unmistakable shape of a unicorn, white and stern, its horn a pale purple. Ralph and Zane joined James there and saw the same thing.
"The Rider," James said quietly. "The one from the tapestries in Erebus Castle! This was his ship. His and the unicorn that came with him."
"How can that be?" Ralph queried in a low voice. "When the Rider came through, he arrived somewhere back home, in Europe, in the Middle Ages, didn't he?"
James shook his head. "These portals aren't like normal doorways," he replied. "I don't think time or distance make much difference with them. The Nexus Curtain may always be there, connecting to our world, but it probably looks different every time it opens. It may open up into entirely different times and places in our world. There's no way of knowing."
Zane was barely listening. He was moving along the hull of the abandoned airship, studying the symbols painted onto it. "Look," he said, touching one of the drawings. "The unicorn that came through with the Rider wasn't just a regular beast. You can see that just by looking at the way it's painted. It was smart. It wasn't the servant of the Rider."
"They were partners," Ralph agreed, leaning to peer at the drawings. "They were explorers."
James shook his head darkly. "Too bad their explorations led them here."
They knew the dangers they faced, a thin, ghostly voice said in James' ear.
The three boys startled and spun around, their eyes bulging. Behind them, staring at them with sad curiosity was a wispy grey shape, almost invisible in the flat light of the plateau. It was the figure of a woman, young and moderately pretty, with huge eyes and a small, sad mouth.
Sorry, she said faintly. I didn't mean to frighten you.
"Are you a gh-gh—," Ralph stammered, his face going white. "A ghost?"
"Oh good grief, Ralph," Lucy said, approaching and shaking her head. "You had a ghost teacher for the last two years at Hogwarts."
"Yeah," Ralph admitted a little defensively. "Well, it's one thing to have a scheduled class with one. It's another thing to have one whisper in your ear when you're exploring some weird dead island."
Sorry, the ghost said again, drifting backwards. It's been so long since I've seen anyone. I forget what it's like to deal with the living.
"Who are you, miss?" Petra asked, tilting her head thoughtfully.
My name is Fredericka, the ghost answered, and made a dutiful curtsy with her transparent hands. Fredericka Staples. I've been here ever since I… She paused before finishing, as if she was embarrassed or reluctant to admit it. Um, ever since I died.
"Fredericka Staples," James said, his eyes widening. "You're the one who… the woman that Magnussen…! Er!"
The ghost nodded and pressed her lips together, obviously not wishing to discuss the topic.
"Who?" Lucy asked, but James shook his head.
"She died on the campus of Alma Aleron," he answered quietly. "She was a Muggle and she got mixed up with the wrong dark wizard. I'll tell you the rest later if you really want to know."
"I don't," Lucy said quickly. "Pleased to meet you, Miss Staples. I think."
"But I thought there weren't any ghosts at Alma Aleron," Ralph commented.
Zane shrugged. "I don't think we're in Kansas anymore, Toto."
Ralph rolled his eyes. "I don't know what that means."
Lucy said, "It means we aren't at Alma Aleron anymore, are we? The regular rules don't apply."
"Perhaps," Petra mused, as if to herself. "Perhaps this place is the reason there are no ghosts at Alma Aleron. Perhaps the portal into the World Between the Worlds is like a ghostly magnet, sucking them in or driving them away, or even both at the same time."
"But that can't be right," James said. "Nobody can get through the Nexus Curtain without the proper key."
"I think that's only true for the living," Izzy commented thoughtfully. "The dead can get through all kinds of doorways that were closed while they were alive."
The ghost of Fredericka Staples nodded. When I died, there was a huge white light. I knew I was supposed to go to it, but I didn't want to. I wasn't ready to leave yet. I was engaged to be married, you see. My life had barely just begun and I didn't really know then that I had died. Not really. The light drew me to it, but I resisted it. And then, as I pushed back from the white light… something else began to pull at me. It was like the opposite of the white light… it was… a black hole, sort of. It was strong and I couldn't control it. It pulled me in, and then… suddenly… I was here. At first, I thought this was the afterlife, but not for very long. It wasn't either heaven or hell. It was just… here. And there were people here, sometimes.
James blinked. "You've seen people here?"
Fredericka looked at him and then gestured toward the ancient airship. More of the ships came once, a long time ago, she said in her thin, far-off voice. They looked just like that one, only bigger. They saw me and spoke to me. They'd traced the journey of the ones who came in that ship and asked me about them. I told them I was sorry, that I didn't know anything about their missing friends. Then they used their tools to learn the truth—that evil magical people had captured the man and the unicorn and killed them—and then they discovered that the same had happened to me. They learned more, though. They learned that not all of the people from our world are like the ones who committed those acts. There are good ones among us, always fighting the bad, but the balance of power is forever changing. They determined that our world was too dangerous for them to explore, and built the black castle as a warning. It's been there ever since, empty and silent. Until very recently.
"You saw someone else," Petra said. It wasn't a question, but Fredericka nodded anyway, turning her attention to her.
I saw, but I didn't approach. I hid. I knew it was safer that way. Being a ghost has its benefits. Hardly anything can scare you anymore. But some things are worse than death. I hid and I watched.