I'm currently on Planet of the Dead as part of my entire Doctor Who series marathon which I started this time last year. I feel like this wasn't explained; or it was explained, and I just didn't get the memo.
What exactly was binding the Doctor and Donna together, and more importantly, what for? Was it something that was established in Journey's End or The End of Time? Was it the Ood, Davros? The Rani?
I somehow get the feeling that it was to teach the Doctor a lesson, but I'm still a bit in the dark.
What exactly was binding the Doctor and Donna together, and more importantly, what for? Was it something that was established in Journey's End or The End of Time? Was it the Ood, Davros? The Rani?

I somehow get the feeling that it was to teach the Doctor a lesson, but I'm still a bit in the dark.
) and kept things on track between The Doctor and Donna. It isn't suggested in this case, no need for suggestions, we see and later learn about those moments. Caan's words were indeed a prophecy to Davros and the Daleks but not to Caan. 