Grand Theft Cosmos ( audio story ) Publisher ' s summary . " Here ' s to crime , Doctor ! " The Doctor and Lucie visit nineteenth - century Sweden and become embroiled in an attempt to steal the infamous Black Diamond . But the stone is guarded by forces not of this world . . . Plot . Aboard a train , the Doctor and Lucie talk about their trip and about the train they are riding . The year is 1898 , and though Lucie is enjoying herself , she would rather be using her MP3 player . They part ways , the Doctor going to find some food , Lucie going to the observation car . Unknown to either of them , Lucie ' s former coworker from Hulbert Logistics , Karen Coltrane , knocks out a guard , then picks a lock to enter the security compartment . The head of security , Henrik , confronts her ; she offers not to shoot him if he tells her where to find what she is looking for . In the dining car , the Doctor meets a man named Frederick Simonsson , who talks with him about the train , and about their destination : Stockholm . Simonsson explains that he works for the king , acquiring art for the king ' s collections and for museums . Elsewhere , Lucie bumps into Karen and is shocked to find her alive ; before Lucie can find out how Karen came to be in 1890s Sweden , Karen makes a distraction and runs away . For the Doctor and Simonsson , the conversation turns to art . Simonsson reveals he is trying to collect the works of one Claudio Tardelli , whom he believes to be Italy ' s greatest artist . The Doctor knows the name ; few of his works survive . Simonsson intends to unite any remaining works ; he already has two paintings and one statue , and is just returning from acquiring another piece . At that moment , Henrik arrives and announces that a thief is aboard the train . Meanwhile , Lucie is chasing the thief in question , Karen , who finally reaches the end of the train . At the last door , she finds her partner , the Headhunter , pacing the train on horseback ( instead of the expected hover platform ) ! Karen manages to leap to the horse as Lucie arrives ; as Lucie tries to process the presence of her old enemy , Karen confirms that she has what they came for , and the duo rides off . It seems that Karen was after the Tardelli work . The Doctor offers to help Simonsson retrieve it , but Simonsson declines ; he says that the actual work was never on the train , and the thieves have stolen a decoy . He shows the Doctor photographs of the other Tardelli works , some of which don ' t fit the artist ' s usual style and were likely commissions ; one , in particular , is an abstract work , years before the abstract movement . Simonsson thinks it will revolutionise scholarly perception of art history . Well away from the train , Karen turns over the stolen item : a large diamond . She comments that it is unlike other diamonds , and the Headhunter hints that it is not , in fact , a diamond ; however , she realises that it is a fake . With their first plan now thwarted , the Headhunter sets out a new plan . Meanwhile , Lucie rejoins the Doctor and reveals that Karen and the Headhunter are present and are the thieves . The Doctor explains that the Tardelli work was the stolen item . He explains that Tardelli is obscure because he , the Doctor , has worked to make it so ; he had previously met Tardelli and found that his works somehow warp reality , even to the point of changing the people that observe them . Tardelli , as it turns out , was not human ; and he was trying to gain control of the Pope . Although that adventure ended badly for Tardelli , the artist escaped to Florence ; since then , the Doctor has destroyed any Tardelli works he could find . Their presence in the home of the otherwise - respected King Oscar of Sweden is a dangerous development ; and the Headhunter ' s presence is even more disturbing . He decides that they must steal the real work of art before the Headhunter can do so . Arriving in Stockholm , the Doctor and Lucie examine the outside of the island - based Drottningholm Palace , where the art is supposed to be kept . If they can locate the paintings inside , he can take the TARDIS in and scoop them up in one trip ; but they must know , because the TARDIS ' s noise will attract unwanted attention . Nearby , Karen and the Headhunter are watching the Palace as well and see the Doctor and Lucie . They move to put their plan in action ; Karen goes to approach a guard but recognises him from the train and switches tactics , following another man up the steps . Unfortunately , the man is Henrik , who is checking in on the guards . At the same time , Lucie sets a similar plan in motion , faking a faint at the feet of the guard . When the man goes to help her , she accuses him of robbing her ; he offers to get her a doctor , and instead she gets him to accompany her — very reluctantly — to a restaurant . Seeing this , the Headhunter realises the Doctor and Lucie ' s involvement may work to her advantage . Lucie manages to ply the guard , Anders , with wine , until he begins to tell her about the situation at the palace . The King is currently away , with most of his guards with him ; due to the events on the train , the rest of the guards are on alert for anyone trying to steal the new work of art , which is arriving tomorrow . It is called the Black Diamond , but he admits that it is not really a diamond . He reveals that it is to be kept in the vault , as are all works not on display . The Doctor joins them and extricates Lucie from the situation , and Anders returns to his post , leaving Lucie to share her newfound information with the Doctor . En route back to his post , Anders is knocked out and kidnapped by the Headhunter and Karen . After debating with Lucie about whether their plan constitutes a crime , and whether it is justifiable , the Doctor and Lucie return to their hotel to test some equipment . Meanwhile , the Headhunter hypnotises Anders and gives him directions ; tomorrow , he won ' t remember her but will accept her claims to be an aristocrat , Elizabeth of Bohemia . After playing around with the hypnosis , she sets a trigger phrase in Anders ' mind : " Elvis Presley " . The phrase will make him remember speaking to them , and in this era , no one will say it accidentally . The Doctor puts together a machine that creates a short - range feedback loop in a subject ' s brain . He demonstrates its effect to Lucie ; he uses it to cause a book to disappear from her hand , then explains that he actually took the book from her , but the machine caused her not to perceive that event . He intends to use it on the guards . Lucie , using a borrowed aristocratic identity , meets with Simonsson , who has just checked in with Henrik . She offers him the chance to see and purchase a new item , which may be of interest to the scientifically - minded King Oscar . The item is the TARDIS ; Simonsson has it unloaded from a cart and examines it . Lucie persuades him to step inside . He is caught off guard by its internal size ; Lucie claims not to know how it works . The King will be happy with it and invites Lucie into the library to discuss the price ; Lucie claims to be fearful of leaving it outside and asks him to move it into the vault . He agrees . As soon as they enter the palace , the Headhunter arrives in a carriage and executes her own act ; her feigned outrage at the King ' s absence gets her into the palace . Lucie uses a walkie - talkie to communicate with the Doctor , who is inside the TARDIS with the door locked . He intends to claim the paintings immediately but may have to come back for the statue , which is twelve feet tall . The Headhunter has her own walkie - talkies and contacts Karen , who is on the roof , trying to bypass the guards en route to the cellar . While Lucie talks with Simonsson , Anders arrives and explains to Simonsson about " Elizabeth of Bohemia " , whose demand to wait for the King ' s return is simply not possible . Simonsson goes to talk to her and takes Lucie with him ; she is shocked to see that " Elizabeth " is the Headhunter . Lucie makes her excuses and leaves ; the Headhunter warns Simonsson against associating with Lucie , who she alleges to be lying about her status . Meanwhile , Anders and Henrik supervise the arrival of the Black Diamond . They take it to the Vault , but Anders insists on putting it in a different case than planned to thwart any would - be thieves . Meanwhile , Lucie warns the Doctor about the Headhunter . He already has the paintings and is waiting on the Diamond to arrive ; he has the feedback device ready for the guards but warns Lucie to turn on her own neuristor device , which prevents her from being affected . As Anders and Henrik arrive in the vault , they hear a noise , and suddenly the diamond is gone . They retrace their steps , searching , when they run into Lucie , who runs off . She reaches the TARDIS and goes inside ; but when the Doctor checks the Diamond , he finds it is the fake that Karen stole on the train . Where is the real Diamond ? Meanwhile Karen makes her way to the vault , where she finds Anders . She uses the " Elvis Presley " phrase to place him in a trance ; he confirms that he switched the real Diamond for the fake , as per the Headhunter ’ s instructions . He gives her the real Diamond , and she tells him to escort her out — but the statue comes to life and starts pacing toward them . They run from it . The Doctor sees the statue moving on the scanner but has to leave that for later ; right now he needs to find the Headhunter and Karen . He moves the TARDIS to the main hall , where it happens to materialise just as Anders and Karen arrive . The Doctor and Lucie exit and demand the real Diamond , but Karen sets Anders to delay them while she runs . Anders draws a sword , forcing the Doctor to grab a sword from a wall display and fight back ; the Doctor sends Lucie to stop Karen . The Headhunter is still with Simonsson in the library when Karen runs in with the statue behind her . The statue demands the Diamond and grabs Karen ; the Headhunter tells her to throw the Diamond to her , promising to help her later . She throws it , but it lands on the floor just as Lucie races in to scoop it up . Lucie runs back out , taunting the Headhunter and Karen as she does so . The Headhunter shoots the statue with a laser weapon , stopping it ; Karen is not amused when the Headhunter explains that she hesitated so as not to hit Karen . The Headhunter knocks out Simonsson to stop him from interfering . Lucie finds a carriage outside , but the driver is working for the Headhunter to stop anyone else from leaving with the Diamond . In the interim , the Headhunter and Karen arrive and take Lucie hostage , ordering the driver to take them all to the station . Simonsson awakens and assumes to Henrik that the Doctor and the three women are all accomplices . The guards bring the Doctor in to be interrogated , but it soon becomes clear that they are not accomplices after all . He tells the truth about Tardelli ' s works ; when Simonsson denies any ill effects , the Doctor attributes it to the brevity of Simonsson ' s exposure to the actual works . The statue starts moving again as it shrugs off the effects of the laser . Faced with a situation he can ' t explain , Simonsson offers to help the Doctor recover the Diamond . They leave in the TARDIS . Meanwhile , the Headhunter , Karen , and Lucie board a train which will leave for Russia in ten minutes . Karen tells Lucie that this is all business , not evil ; the Headhunter explains that she took Karen on as a personal assistant . Karen is still angry at Lucie for leaving her for dead at Hulbert , however . The Headhunter explains that there is a purpose to this heist . She tells the Diamond to " come out " , at which point an elderly man appears in the compartment . He is Claudio Tardelli , and the Headhunter wants to offer him a job . He has been inside the diamond — which is bigger on the inside — since the seventeenth century . The TARDIS materialses at the station , disgorging the Doctor , Simonsson , Henrik , and several guards . Simonsson sends Henrik to stop all departures while the station is searched . Tardelli explains that the Diamond contains a small , artificial universe three light years across , which he created as a bolt - hole . He is from the planet Parrimor but was exiled to Earth . The Headhunter explains that she represents the Emperor Vassilar - G of Ralta , who wishes to hire Tardelli as a well - compensated court artist ; but she intends to give the Diamond to a Russian named Yashin , who wants to use it for energy for his industrial endeavours . Tardelli agrees to cooperate in return for a share of the Headhunter ' s profits . As the guards approach , the Headhunter says that she has already hypnotised the driver of the train to leave at the first sign of trouble . The Doctor and Simonsson manages to hop the train as it leaves , but Anders and Henrik are left behind — and communications with the next station are down . The statue arrives and follows them as the train pulls away . Karen reveals that the Doctor and Simonsson have arrived ; Tardelli is frightened at the mention of the Doctor . The Headhunter declines to use her ship ; the ion engines could fracture the Diamond , which would be catastrophic . The Headhunter tells Karen to shoot Lucie if there is any trouble . The Doctor and Simonsson find and open the compartment , only to find Karen holding a gun on Lucie . Tardelli comments that the Doctor looks different from their last meeting . The Doctor identifies Tardelli for Simonsson ' s benefit ; but when Simonsson learns about the pocket universe — and the people Tardelli has created inside , but will soon destroy — he is appalled at the artists character . Suddenly the statue breaks in through the roof . Tardelli tells it to stand down , as he is safe ; but Lucie realises its orders are to protect the Diamond , not Tardelli . The Doctor uses this to delay the creature ; but the Headhunter escapes with the Diamond , leaving Karen behind . Lucie overpowers Karen and takes her gun , and the Doctor gives it to Simonsson to cover Karen and Tardelli while he and Lucie chase down the Headhunter . The statue cuts her off at the other end of the carriage , trapping her between itself and the Doctor . Lucie manages to kick the Diamond out of her hand ; when the Headhunter insults her , Lucie knocks her out . The Doctor tells the statue that the best way to protect the diamond ' s population is to free them . He rejoins Simonsson , who is discussing art with Tardelli . The Doctor reveals he has struck an agreement with the Guardian to fracture the Diamond ; now , in a very short time , it will erupt into the real universe , causing a cataclysm . This forces Tardelli to make a fifth - dimensional jump , allowing the pocket universe to emerge into the gap between universes where it can safely survive . It will then be outside Tardelli ' s control , which satisfies the Doctor . Tardelli releases the universe as agreed and then gives the now - useless Diamond to Simonsson . Karen snatches her gun back and takes everyone at gunpoint , but Tardelli reminds her that the Headhunter is still obligated to take him to Ralta for his new job . She allows him to leave with her . However , they happen to meet Lucie coming the other way with the Headhunter in restraints . The Headhunter is horrified to learn that the Diamond is now useless to Yashin , the Russian . He will kill her if he can ; therefore she cannot return to Earth at this time period . She says her goodbyes to Lucie and leaves the train with Karen and Tardelli to summon her ship . Simonsson is disillusioned over his artistic idol , Tardelli . He asks the Doctor to destroy the two paintings in his possession , but the Doctor declines ; he intends to study them and find out if there is a way to display them without their dangerous effects . Destroying them would make any others that much more valuable . Meanwhile , the Guardian is now free of obligations ; Simonsson tells it about legends of stone trolls in the woods near Stockholm , and it leaves for the forest , hoping for a place to fit in . Lucie apologises for letting the Headhunter escape , but the Doctor dismisses it . He declines to visit the former pocket universe , and he declines to follow Tardelli , as the Emperor of Ralta is known to be very fickle — he has a reputation for eating artists who fall out of favour . Instead , it ' s dinnertime . . . and they make their way back to the city .