The Unicorn and the Wasp (TV story)

Synopsis
In 1926, Agatha Christie mysteriously disappeared, only to be found ten days later, with no memory of what had happened. Was it a nervous breakdown? A cry for help? Or perhaps a giant alien wasp..?

Plot
The Doctor and Donna Noble arrive in time for an afternoon party at the Eddison estate. The event is hosted by Lady Eddison and her husband, Colonel Hugh Curbishley. One of the guests is famed British mystery writer, Agatha Christie. Still a young writer, she has recently published her sixth novel. Looking at a newspaper, the Doctor finds that it is 8th December 1926, the day of Agatha Christie's disappearance. Just as this revelation is made, Eddison's friend and companion Miss Chandrakala finds another guest, Professor Peach, dead in the library. He was murdered with a lead pipe.

At the scene, Donna comments on the similarity to the board game Cluedo. The Doctor finds "morphic residue" on the floor while examining the scene - morphic residue, a by-product of shapeshifting, implies that one of the guests isn't really human. Agatha discreetly removes a fragment of paper from the grate on the fireplace. The Doctor notices but says nothing. Aided by Agatha, the Doctor interviews the guests while Donna goes looking for clues. During the interviews, while the guests recount their stories, flashbacks reveal that each is hiding something, except Rev. Arnold Golightly.

Lady Eddison claims to having been taking tea, though she was in fact surreptitiously consuming liquor. Robina Redmond, a socialite, claims to have been using the toilet, but is shown loading a tiny pistol there. Roger Curbishley, Lady Eddison's son, claims to have been walking, alone, failing to disclose he was attending a tryst with his lover, Davenport, who is one of the servants. Colonel Hugh Curbishley claims he was reading military memoirs in the study, though he was actually viewing erotica while fantasizing about can-can dancers.

After the interview, Agatha Christie produces the paper she removed earlier which contains the letters "a-i-d-e-n", preceded by one illegible letter. Agatha points out that it obviously spells the word "Maiden", although neither she nor the Doctor is able to divine the significance of this. When Donna investigates a locked room in which Lady Eddison had sequestered herself, for six months, while allegedly recovering from malaria, she is alarmed by a giant wasp outside the window. Donna uses a magnifying glass to focus the sun's rays on it, injuring it and allowing her to flee. The insect chases her, impaling its stinger on a door.

Davenport is in the kitchen, speculating about why someone would want to kill Professor Peach. Miss Chandrakala is also there, and dismisses this as "dead man's folly" until she suddenly realises exactly what Professor Peach was doing. Rushing off to warn Lady Eddison, she is killed when an unseen figure hurls a gargoyle from a ledge--and hits her head.

Hearing her scream, the Doctor, Agatha, and Donna rush outside; Miss Chandrakala dies on the scene, cryptically offering "The poor little child..." as her last words. Seeing the Vespiform hovering above the building, the Doctor gives chase, but loses the creature in a hall. When the Doctor shouts "show yourself," all of the doors open and every suspect appears.

After the guests pile pressure on Agatha to solve the murder, she retreats to the garden. Donna goes out with her to comfort her, comparing her similar trouble with men. Even though Agatha refuses to believe in her own brilliance, she discovers a box filled with the tools of a thief.

While the three mull over the evidence they've gathered thus far, and Donna accidentally gives Agatha the idea for Miss Marple, the Doctor is poisoned with cyanide. While cyanide is always fatal to humans, Time Lords can neutralise the poison and expel it--if they ingest an odd combination of ingredients (ginger beer, proteins (in walnuts), salt (in anchovies, as pure salt is "too salty")) followed by a shock (a kiss from Donna).

Recovered, the Doctor "poisons" the guests' dinner with pepper; naturally, this is not harmful to humans, but is poisonous to wasps. A buzzing sound can be heard moments later, at which Lady Eddison exclaims, "It can't be!" The lights are blown out by a sudden wind and they again fail to ascertain the identity of the alien. Roger, Lady Eddison's son, is murdered in the confusion, and Lady Eddison's necklace, 'The Firestone', is stolen. In the sitting room, the Doctor and Agatha reveal several secrets about the guests and hosts. Robina Redmond, one of the guests, is a thief, the titular Unicorn, who coveted the Firestone and stole it in the confusion; however, she is not the killer. The truth of Lady Eddison's bout of malaria is also revealed; she was actually pregnant, and not by another human being. The alien was a Vespiform, and gave her the Firestone necklace. The necklace is psychically linked to their son, whom she had given up for adoption and never seen again: Reverend Golightly.

It was Golightly who killed Professor Peach, when he learned that the Professor had discovered his adoption paperwork. He then attempted to burn the paperwork: the word "Maiden" on the paper Agatha plucked from the grate had in fact said "Maiden Name".

Because Lady Eddison had been reading The Murder of Roger Ackryod when her son's alien biology was first awakened in a moment of anger, Golightly accidentally received the works of Agatha Christie as his template for how the world should work: hence the style of the murders.

Enraged at being discovered, Golightly assumes his wasp form. Agatha snatches the Firestone, screaming that her mind--that which had taught the Vespiform to kill--will find a way to destroy him. Golightly pursues her, as her thought patterns are linked to him through the Firestone. She takes a car and drives away, hysterically repeating "It's all my fault." The Doctor and Donna follow her in another car, belonging to the deceased Professor Peach, with the Doctor ominously warning that "time is in flux" - that there is no guarantee that Agatha will survive, which could leave history severely damaged.

Agatha leads the creature to a lake. The Doctor tries to persuade Golightly that he was not meant to kill, but he does not listen. Donna seizes the opportunity to snatch the Firestone and hurl it into the water. Golightly pursues it and drowns, like his father had, in the Indian monsoons forty years before.

Still linked to the necklace, Agatha nearly dies, but Golightly unaccountably chooses to release her as his last act. The psychic trauma causes retrograde amnesia, and the Doctor deposits her at the Harrogate Hotel ten days later, fulfilling the demands of history.

In the TARDIS, the Doctor produces one of Agatha's novels, and points to the copyright page in the front. The publication date is listed as the year five billion; Agatha Christie is quite literally the most popular writer of all time. The novel in question is Death in the Clouds a novel which features a wasp. Agatha Christie had somehow remembered bits of her adventure with the Doctor and Donna.

Cast

 * The Doctor - David Tennant
 * Donna Noble - Catherine Tate
 * Agatha Christie - Fenella Woolgar
 * Lady Clemency Eddison - Felicity Kendal
 * Reverend Golightly - Tom Goodman-Hill
 * Colonel Hugh Curbishley - Christopher Benjamin
 * Robina Redmond/The Unicorn - Felicity Jones
 * The Hon. Roger Curbishley - Adam Rayner
 * Greeves - David Quilter
 * Davenport - Daniel King
 * Professor Peach - Ian Barritt
 * Miss Chandrakala - Leena Dhingra
 * Mrs Hart - Charlotte Eaton

Food and Beverages

 * Donna orders a sidecar and the Doctor orders a lime soda.
 * Donna and Agatha Christie drink orange juice and Golightly tries to poison the Doctor by sliping cyanide into an unknown drink.
 * The Doctor consumes ginger beer, walnuts and anchovies to cure himself.
 * The Doctor laced the soup with pepper.
 * Donna mentions the Harvey Wallbanger cocktail at one point.

References to Agatha Christie novels & short stories

 * Donna inadvertently causes the creation of Miss Marple and the story of the murder in the Orient Express. Although Christie loses her memories of these events, the Doctor tells Donna later that they would unconsciously influence some of her later works, such as Death in the Clouds which features a wasp.
 * Another potential influence occurs when the Doctor is poisoned and Christie is heard to utter the words "sparkling cyanide", which happens to be the title of her well-known 1945 novel.
 * The Colonel faking his inability to walk and the Unicorn posing as Robina Redmond are ideas taken from the Christie novel After the Funeral.
 * Novel titles referenced in the episode are:
 * "Dead Man's Folly", Mrs. Chandrakala's description of the Professor's book (as in 'a dead man's folly'; not the actual name of the book).
 * "The Body in the Library", Donna's remark about the professor's death
 * "Cat Among the Pigeons", a servant's remark about the murder.
 * "Nemesis", Agatha's nickname for the murderer;
 * "The Secret Adversary", Agatha's nickname for the murderer;
 * "N or M?", the Doctor's question to Agatha about the piece of paper she found;
 * "Murder on the Orient-Express", Donna mentions it to Agatha Christie, unaware that the book hasn't been written yet;
 * "Why Didn't They Ask Evans?", the professor's remark before he dies is "Why didn't they ask... heavens";
 * "They Do It With Mirrors", Agatha's explanation about the giant wasp, believing it to be a hoax.
 * "Appointment with Death", Lady Eddison says Chandrakala had " an appointment with death" when mourning over her death.
 * "Cards on the Table", the phrase the Colonel used when he asked Agatha about what she knew about the mystery
 * "Sparkling Cyanide", Agatha Christie says after detecting cyanide in the lemonade
 * "Crooked House", How Agatha desribes the history of Eddison Manner.
 * "Endless Night", how the Doctor desribes the current murder mystery
 * "Taken at the Flood", Lady Eddison said "He was taken at the Flood", referring to her Vespiform boyfriend
 * "The Moving Finger", the Doctor phrases "the moving finger points" when interrogating the suspects
 * "The Murder of Roger Ackroyd" the book Lady Eddison was reading when the Firestone activated
 * "Death Comes as the End", Agatha says "Death comes as the end, and justice is served" after Golightly's death
 * "The Murder an the Vicarage", the Doctor says "Murder at the Vicar's Rage" after Golightly's death, though he believes it could do with some work
 * Yellow Iris a short story included in The Regatta Mystery and Other Stories., at the dinner where the Doctor spikes the soup with pepper, there is a vase of yellow iris as a table centrepiece. It was later expanded to novel length as Sparkling Cyanide.

Story notes

 * This episode is the 50th episode of the revived series of Doctor Who.
 * In terms of principal photography, this is the second story shot in the fourth series.
 * A different opening and conclusion to the episode were filmed. The two scenes take place in the mid-1970s and feature another actress playing the aged Christie, who begins the episode by having flashbacks and dreams relating to her adventure of some 50 years earlier. The ending of the episode featured the Doctor and Donna visiting Christie, upon which she begins to remember what happened and is shown a copy of the facsimile edition of Death in the Clouds from the year 5 billion. When it was decided to abandon the framing sequence, this second scene was remounted in the TARDIS. Both scenes were presented to the public for the first time in the 2008 DVD box set of Series 4.
 * Some of these characters resemble Cluedo characters.
 * Clemency Eddison resembles Mrs Peacock
 * Robina Redmond resembles Miss Scarlet
 * Colonel Hugh Curshiby resembles Colonel Mustard
 * Professor Gerald Peach resembles Professor Plum
 * Miss Chandrakala resembles Miss White
 * Reverend Arnold Golightly resembles Reverend Green
 * In addition, some variations on the game include a 'Miss Peach' character, including the colour of the unfortunate professor from this episode.
 * David Tennant's father makes a cameo as a footman.
 * Graeme Harper's penchant for including a distorted image of a main character is present in this story. Though not included in every single story he's directed for BBC Wales, it's seen often enough to be considered something of a directorial "signature". Similar distortion is achieved through the use of other magnifying glasses in Army of Ghosts and Utopia, a curved window in Journey's End, and with mirrors in Turn Left. This time, it's Donna's face that gets "the Harper treatment".
 * The Agatha Christie book the Doctor produces from the trunk underneath the Tardis is a Fontana Paperback fascimile edition, which were published in 1987. Presumably the Year 5,000,000 copyright page was somehow transplanted in.
 * Felicity Kendall, who plays Lady Eddison, was one of the stars of the classic BBC situation comedy, The Good Life. Her co star, Richard Briers appeared in DW: Paradise Towers as the Chief Caretaker, and in the Torchwood episode A Day in the Death as dying millionaire Henry Parker.
 * Christopher Benjamin had previously appeared in DW: Inferno and The Talons of Weng-Chiang.
 * The Doctor's description of his cyanide poisoning as involving "inhibited enzymes" approximates the actual mechanism of cyanide toxicity. Cyanide inhibits the enzyme aa3 by binding to the iron that it contains, reducing the ability of the cell use oxygen to create the compound ATP, used for cellular energy transfer. Since 95% percent of ATP production in the Human body (and presumably also Time Lords) is aerobic, mortality via energy starvation quickly follows. The Doctor's method of uninhibiting the enzymes, however, is not based on a real remedy (for humans, in any case).

Ratings
to be added

Myths and rumours

 * Due to actress Billie Piper being seen on set it was thought that the unicorn was in fact Rose Tyler. This was false.
 * Brief glimpses of the giant wasp in this episode were included in the first Series 4 trailer; leading to speculation (since the view is too short to definitively identify the species) that this was a reference to the ongoing theme of disappearing bees. This was also false
 * Similarly, the brief glimpse in the trailer of the actress who plays Clemency Eddison, who resembles the actress who played Lady Cassandra in Series 1 and 2, led to speculation that Cassandra would appear in this episode. This was also false
 * At the beginning of the episode, the phonogram plays a march and the first notes are reminiscent of the Master's theme. This was true

Studio

 * Upper Boat Studios, Trefforest

Location

 * Llansannor Court, Vale Of Glamorgan
 * Tredegar House, Newport
 * Pen Y Lan Road, Newport
 * Cefn Mably Lakes, Cefn Mably
 * Hensol Castle, Hensol

Production errors

 * Christie mentions the 'trick' of a giant wasp is done with mirrors but how come she doesn't notice no mirrors of such nor noticing the real life vespiform look

Continuity

 * The Doctor suggested to Martha Jones in DW: Last of the Time Lords, that they take a trip to see Agatha Christie, but was unable due to Martha leaving at the time. Ironically, this is not long after Martha has left again.
 * During the final scene, the Doctor produces a replica Agatha Christie paperback book printed in the far future. Although not an obvious cliffhanger on the order of the ending to many First, Second and Fifth Doctor stories, it does nevertheless establish the fact that traditionally bound books are still produced long after electronic editions would presumably have made them obsolete. In this sense, it may be seen as at least narratively linked to the next episode broadcast DW: Silence in the Library, which begins with the Doctor discussing how printed books continue on as a valuable resource into the far future.
 * This is the third time a famous author or playwright has appeared in the revived series: Charles Dickens (DW: The Unquiet Dead), William Shakespeare (DW: The Shakespeare Code) and now Agatha Christie.
 * The Doctor displays the ability to tell a time period by smell, (which may have been faked due to the vintage car in the driveway). However, he previously displayed this ability in WC: Scream of the Shalka. Such an ability is also referenced in BFA: The Eye of the Scorpion (although, in this, the Doctor admits to having seen ancient texts on the wall behind the TARDIS). Later, in DW: The Eleventh Hour, he demonstrates a similar ability to determine age by taste.
 * Donna stated that solving a mystery with Agatha Christie is like "...meeting Charles Dickens, and he’s surrounded by ghosts. At Christmas.", to which the Doctor replies "Well...", recalling his adventure involving those exact same circumstances (DW: The Unquiet Dead)
 * The Doctor and Donna are (again) mistaken for to be a couple, this has previously occurred in DW: The Fires of Pompeii, Planet of the Ood and The Doctor's Daughter.
 * When Doctor remembers being in Belgium, he is carrying a bow and quiver, as he was when he met Sally Sparrow. It is possible that the adventure to save Charlemagne from "an insane computer" happened at around the same time. (DW: Blink) It is also possible that the bow and arrows were re-used in either incident (first obtained in one incident and re-used in the other) because when Sally Sparrow encounters the Doctor and Martha with the bow and arrows, Martha mentions 'hatching time' and 'migration' inferring that they need the bow and arrows to shoot (possibly) some sort of space-bird, so the two incidents couldn't have happened right next to each other.
 * Donna compares her fiancé's conspiracy with the Empress of the Racnoss to Agatha's marital troubles. (DW: The Runaway Bride)
 * With this episode, Donna becomes the latest female companion to kiss the Doctor on the lips.
 * The Doctor brings out the Carrionite sphere and a Cyberman logo in a chest of things beginning with C. (DW: Rise of the Cybermen / Age of Steel, The Shakespeare Code)
 * This is not the first occurrence of interspecies intercourse. There are many references throughout the series, including a reference in DW: The Doctor Dances to it being one way in which humans so quickly propagated themselves throughout the galaxy "So many species, so little time")
 * Agatha Christie is one of several people to demand to know who the Doctor is, only to receive no real reply. Charles Dickens, Solomon, Trish Webber, the passengers of the Crusader 50, and Metella Caecilius Iucundus are but a few of the others who have fruitlessly questioned the Doctor's identity.
 * This is the third time that the Doctor has told a companion not to imitate a period dialect. The first was Rose doing a (poor) Scottish accent in DW: Tooth and Claw and the second was Martha imitating Elizabethan English in DW: The Shakespeare Code. This time Donna attempts an over-exaggerated upper class accent.
 * In BFA: Terror Firma the Doctor claims that Agatha Christie traveled with him.
 * Donna gives Agatha ideas similar to how the Doctor did with William Shakespeare. (DW: The Shakespeare Code)
 * Lady Eddison calls Chandrakala her "faithful companion", the Master uses the same two words for Lucy Saxon. (DW: The Sound of Drums')
 * Though she is probably simply using the stereotypical name for an alien planet, Donna makes reference to the planet Zog, which is later seen in (DW:The End of Time).
 * What happens to Agatha Christie is not dissimilar to Donna's own ultimate fate.
 * When Donna was investigating the locked room she heard the buzzing of The Wasp before she saw him. She commented aloud that in 1926 there's still Bumble Bees. The dissapearance of Bumble Bees is frequently mentioned during Series 4. In the real world both Bumble Bees and Honey Bees are dissapearing from the globe, a major concern.
 * When Donna begins to remember her adventures with the Doctor, she asks Wilfred why she can see a giant wasp, a reference to the Vespiform. (DW:The End of Time)

Home video releases

 * Released in the Series 4 DVD boxset in November 2008 along with the rest of the Series.
 * Released as Series 4 Volume 2 in a vanilla edition alongside The Sontaran Stratagem, The Poison Sky and The Doctor's Daughter.