Theory:Doctor Who television discontinuity and plot holes/The Stones of Blood


 * How does de Vries control the ravens, and what is their function?
 * She does have access to powerful technology and this power would convince her followers she had powers. Also birds would make good spies.
 * De Vries is a he.
 * To put it more clearly, Cessair has the powerful technology, up to and including the Great Seal of Diplos. She controls the ravens with these. She instructs them to follow de Vries' orders to create the impression that he is controlling them.


 * At the start of the story there are three Ogri. One falls off a cliff, but later there are still three.
 * Perhaps it survived the fall.
 * When questioned about its seeming death moments afterwards, the Doctor admits he isn't sure if the fall could kill it, so it seems a safe bet that it couldn't.


 * If Cessair has escaped from the prison ship, why does she stay on Earth? What's her plan?
 * If we knew that it wouldn't be that much of a secret plan. Why should she leave when she has her liberty? Besides, how could she leave without a ship of her own. It is even conceivable that she is an agent of the Black Guardian or the Shadow, and has been awaiting further orders (not knowing that the Shadow has changed his plan, and is allowing the Doctor to gather up the five segments, thus leaving her expendable).
 * Likewise Cessair is a galactic con artist who's enjoyed four thousand years of having absolute power over her own fiefdom. Maybe she's simply smart enough to know when to quite whilst she's ahead (trying to say conquer the whole world or even the country with the same bag of tricks would be unfeasible considering her, powerful but still limited, resources), and is content to simply sit back and enjoy the splendour, whilst she waits for a better mark to come along.


 * Why did the ship get stuck in hyperspace?
 * Cessair may have used her "wand" device to disable it, and prevent it from materialising into real space.


 * Why would Cessair be content to live in her tiny cottage when she could still be at de Vries' mansion?
 * She seems to have been forewarned of the Doctor's arrival: de Vries is prepared to encounter him, and even knows his alias. That might also account for the White Guardian's warning at the beginning of the episode. Though there is nothing to explicitly identify her as such, it does seem possible that Cessair has been working on behalf of the Black Guardian on a similar segment-gathering mission as the Doctor.


 * The line of empty portrait spaces in de Vries' hall implies that at some point, all four portraits of Cessair (under her various aliases) were hanging next to each other, thus allowing all to see that their subjects are the same person. Why would Cessair ever allow this to happen and run the risk of blowing her cover?
 * The fact that she has moved out of the mansion (as noted above) and started using de Vries and the BIDS as a front suggests that she has been fairly complacent about her secrecy until recently, perhaps having been forewarned (maybe by the Black Guardian) that someone would soon come looking for the Great Seal / Third Segment.
 * Considering she's a con artist and her MO is fooling people into thinking she's a mystical being, perhaps the pictures were deliberately arranged like that as another part of the theatrics (i.e. feature servants or threats noticing the clear resemblance and thus realising their dealing with a being of great power than they can understand, without her having to say anything out loud and risk overplay her hand). After that it would only require a few other displays to completely sell the con.