"It is Time Lord technology. I think, really, it is like a tear in a paper, held open by fingers, sealed shut again by the machines as if it were glued back up," she said, frowning. "I should explain more. The Time Lords are a race of people who have the technology to travel through space as well as time, it is they who set up these portals many, many years ago. I think, it was an attempt to monitor the other timelines, perhaps. Brax would explain it better or perhaps even the Doctor himself - he is a Time Lord - but I do not know where he is, now. The last one of him I saw was not my own Doctor. He was different, a hunter like I am."

Leela glanced at Capa for a moment.

"It is all right. Even I am confused by my own life sometimes. Time travel is a complicated thing and it would take the whole of the rest of my life to explain things properly."