Theory:Doctor Who television discontinuity and plot holes/The Unicorn and the Wasp


 * Donna investigates a room in the manor house - which has been locked for forty years. However, in the room, there is a teddy bear. Teddy bears were introduced (and became popular) at the turn of the 20th century.
 * It being actually locked for forty years probably wasn't literal, as the room would have to be opened, etc. It is also possible that the room has just become a storage space. It could also be a misplaced hint that Lady Eddison had a child in the room, since a teddy bear is usually a child's toy.


 * The "thieves in the night" at the church seemed to be committing their crimes in broad daylight.
 * Rev. Golightly is making a Biblical allusion: see 1 Thessalonians 5:2.


 * Agatha mentions her extensive study of poison, claiming that cyanide poisoning is invariably fatal. In reality it can be countered by several methods, including the administration of nitres, hydroxocobalamin or certain chelants. It is surprising that she sniffed the drink, as hydrogen cyanide is one of many poisons that can readily be absorbed via inhalation. Ms. Christie gained her knowledge of poisons by working in a V.A.D. dispensary during WWI, so she would have known this in 1926. (See The Agatha Christie Companion by Sanders and Lovallo. ISBN 0425118452)
 * This may have only been found out in the future. It may have not been known then.
 * The cyanide mixture clearly was not potent enough to kill her through inhalation, especially given that she took only a quick sniff. As for the counteraction methods, they would have possibly been useful if they had been in a hospital (or dispensary perhaps), but the knowledge would have been of precious little value for her to impart at that point.


 * How could the Vespiform hold the lead piping?
 * With one of its arm/legs or a mandible. Even it could, why would it kill with a lead pipe when it could stab with its stinger.
 * The alien was acting out murder-mystery plot tropes, remember, his mind is linked to Agatha's novels, which is why he sets about killing people in the first place.


 * Even though it turns out that Reverend Golightly tried to poison the Doctor, why did the Butler still give him an odd look?
 * A reference to the good old plot device of "the Butler did it". Furthermore, the Doctor's behaviour is frequently odd enough to draw suspicious glances.


 * Agatha disappeared in December which is in the Winter and the weather is that of a summer or spring.
 * It can be sunny in Winter in England. Plus, it only remains sunny for a while; when Roger dies it is extremely stormy.


 * The Doctor seems to have gotten over Jenny's death pretty quickly.
 * It is likely that some time has passed since her death, and the episode does not mention anything about the previous episode.


 * While the Doctor tells Donna about the Curbishleys at the party, he says Roger will one day become a Lord, but Roger is killed by the Vespiform the very same day.
 * He isn't predicting the future, he's explaining the peerage system. It's quite clear he didn't know what was about to unfold.


 * If it was printed in the year 5,000,000, Death in the Clouds should long since be out of copyright and in the public domain.
 * Copyright laws may be different in the year 5,000,000.
 * I've got a copy of Edwin Abbott's Flatland on my shelves that clearly says "Copyright 1884", along with a note in small print that "copyright expired as of time of printing". Why wouldn't a copy of Death in the Clouds from 5,000,000 similarly list the original copyright?
 * Why would it? Five million years is a very long time, and things do change often in copyright law.


 * In The Shakespeare Code the Doctor says that he has an attic in the TARDIS where the Carrionites can be kept, however, in this episode, they are kept in a chest under the TARDIS floor.
 * They were still screaming in the crystal ball, and may have become annoying in the attic, so he moved them.
 * He may have just never gotten around to putting them up there, or he simply moved them at some point - probably when he was organising "C" items together.

It was probably drawn to the Firestone so much that it forgot. Plus as Reverend Golightly the vespiform might not have known how to swim considering wasps aren't designed for swimming
 * Why did the vespiform not take it's human form and save itself from drowning?


 * Donna's magnifying glass shows a near-pinpoint on the wasp, which means it has a focal length of several metres. Such a magnifying glass would be near-useless for magnifying clues and is inconsistent with the view of her eye through the same glass earlier.


 * There is no way that the Doctor and Agatha wouldn't notice the giant wasp's stinger before Donna pointed it out. When coming across the corridor it would be in their line of sight and its size makes it impossible for them not to notice it