"I don't know who he was, but I did see him," the Doctor confirmed, turning back to Chrno as the boy questioned him. "You didn't see because he halted time, while he moved normally through it."

"Astral line... astral line..." he echoed thoughtfully. It didn't sound familiar.

The Time Lord shook his head. "No, I can't say I have. What's the astral line?" he asked.