Board Thread:Whoniverse Discussion/@comment-20801481-20150908175952/@comment-15395126-20150914031919

I personally find the Prologue to be very straight-forward. It's obvious the Doctor and Ohila are talking about the Master/Missy, at least to me. The Doctor gives that device that is his "last will and testament" to Ohila, and Missy has it in one of the Series 9 trailers, though I forget which one.

What's interesting is it seems this is just the prologue to The Doctor's Meditation.