Let ' s Kill Hitler ( TV story ) Let ' s Kill Hitler was the eighth episode in the sixth series of " Doctor Who " and the first episode in the autumn half . It was , in a sense , the second episode of a two - part story , preceded by " A Good Man Goes to War " . Like " A Good Man Goes to War " , it revealed much about River Song ' s origins , also dealing with Amy and Rory ' s childhood and how they became a couple . Additionally , it explained why the Silence had been trying to kill the Doctor and it is stated that the Doctor ' s death at Lake Silencio is a fixed point in time . At the end of the episode and in following episodes , the Doctor is occasionally seen looking at the information he downloaded from the " Teselecta " on his death . The episode featured the first " Time Lord - style " regeneration of a female that showed the complete change in physical appearance from old to new incarnation on - screen . Previously , such regenerations were shown with the change from an old form already completed or cut out before the physical change even began . " Let ' s Kill Hitler " also dealt with other aspects of regeneration , such as being able to rapidly heal from otherwise fatal injuries while the regenerative cycle was still in process , and a capability to donate some amount of regeneration energy to another at will . This was the first televised " Doctor Who " story to feature the personal appearance of the tyrant dictator Adolf Hitler . However , although the title of this episode suggested the story might revolve around him , in truth he received close to five minutes of screen time and was quickly ejected from the plot . A few references to World War II and Nazi sm were present , but much of the episode focused on the first appearance of the Justice Department and the strange types of technology they utilised . Instead , the title comes from Mels ' demand to be taken back in time to kill Hitler in the cornfield at the beginning . In this episode , the shapeshifting robot known as the " Teselecta " is introduced . The " Teselecta " and her crew make a return in " The Wedding of River Song " where they play an important role in the plot . Unknown until the events of " The Wedding of River Song " , the " Teselecta " also appeared in the beginning of " The Impossible Astronaut " and played a major role there where the two episodes events were connected to each other . Additionally , the episode introduces The Question which is described as " the oldest question in the universe , hidden in plain sight . " While the Doctor learns of the Question from the " Teselecta " , he does not learn what it is or its significance to him . The Question is revisited in " The Wedding of River Song " where the Doctor learns what the Question is from Dorium Maldovar and why it means he must die and in " The Time of the Doctor " where the true nature of the Question and its meaning are revealed . Synopsis . In the desperate search for Melody Pond , the TARDIS crash lands in Thirties Berlin , as the time - travelling drama returns for the second half of the series shown earlier in the year . The Doctor comes face to face with the greatest war criminal in the Universe . And Hitler . Old friendships are tested to their limits as the Doctor suffers the ultimate betrayal and learns a harsh lesson in the cruellest warfare of all . As precious time ebbs away , the Doctor must teach his adversaries that time travel has responsibilities . And he must succeed before an almighty price is paid . Plot . Rory drives through a wheat field wildly as Amy gives directions badly . She is telling him how to trace letters by mowing down the wheat with the car that will spell out a name , trying to summon the Doctor in the loudest manner possible , so that he cannot avoid contact with them any longer by dodging Amy ' s phone calls . Stopping their car , they find the Doctor standing by his TARDIS in a new green pea coat . The trio suddenly learns what caused the unknown stroke in the message when they hear the high - powered engine of a sports car revving through the field and shredding a new line down the middle of their crop circle . All of them start screaming for their lives . They dodge out of the way as a Corvette almost runs them over . Out steps Amy and Rory ' s best friend , Mels , who flirts with the Doctor and fondles the TARDIS . With police sirens prophesying her arrest for car theft , she points a gun at the Doctor and demands he take her to kill Hitler . Flashback : Mels is a childhood friend of Amy and Rory and a troublemaker at school . She gets in more trouble than anyone except boys , insults teachers , continually references the Doctor , steals bus es and points out to Amy and Rory that they ' re in love . Back in the present , the TARDIS flies wildly because Mels has shot the time rotor . He barks at the delinquent , " You shot it ! You shot my TARDIS ! You shot the console ! " Mels accusingly remarks , " It ' s your fault ! " He inquires , " How is it my fault ? " She replies , " You said guns didn ' t work in this place . You said we ' re in a state of temporal grace . " Angry that she fired her gun out of foolish curiosity , he snarks , " Oh , that was a clever lie , you idiot ! Anyone could tell that was a clever lie ! " In 1938 Berlin , a janitor watches a Nazi officer . In a futuristic control room , the crew discuss copying the officer as the janitor follows him . In the control room , a woman complains that the last time they relied on the computer , it " made Rasputin green " . She goes to " the top level " , where an electronic voice politely threatens her until she adjusts a device on her wrist . She looks through a view port , which is the eye of the janitor , actually a highly advanced ship , the " Teselecta " . She relays colour codes to the control room . The janitor becomes the officer ' s double and beams him aboard with a miniaturisation ray . Learning the officer ' s identity as a war criminal , the crew leave him to the antibodies . They politely threaten the officer before killing him . The " Teselecta " enters Adolf Hitler ' s office while the captain complains about the shock - absorbers malfunctioning . Hitler asks why his officer has entered without permission . The " Teselecta " activates " justice mode " and paralyses him with a beam of light from its mouth . However , one of the crew says they arrived too early in his timeline , just before the TARDIS crashes through a window and knocks over the " Teselecta " . The TARDIS occupants stagger out in a cloud of smoke caused by Mels ' havoc . Hitler thanks the dumbfounded travellers for saving him and asks what the TARDIS is . The Doctor advances on him , saying it ' s a police box and " The British are coming ! " The " Teselecta " picks itself up and a panicky Hitler fires at it . Rory punches out Hitler and takes his gun . The Doctor and Amy help up the " Teselecta " . Rory shoves Hitler in the cupboard while the " Teselecta " goes into observation mode — " fainting " . Mels staggers forward . She calls Hitler a lousy shot and collapses ; she was hit by a bullet . Rory tries to help her and the Doctor tries keeping her conscious by talking to her . Mels says she wanted to marry the Doctor and he promises to ask her parents when they fix her up . Mels says they ' re right there , then begins to glow . The Doctor , who recognises that Mels is starting to regenerate , pulls the others away from her . Mels comments about regenerating once before as a child in New York and reveals her actual name to be Melody . Amy says she named her daughter after her , but the Doctor explains , " You named your daughter after your daughter " and Mels finally regenerates with a scream . The crew of the " Teselecta " look in bewilderment at a criminal whose crimes dwarf Hitler ' s : Melody Pond . Melody ends her regeneration in her River Song incarnation . She chatters on about her new look before going off to weigh herself . The three time travel lers talk , realising that Melody is River Song right at the beginning . Melody asks who River is , but the Doctor refuses to tell her " spoilers " . She pulls out a gun , " getting back to business " , points it at the Doctor and pulls the trigger . The gun , emptied by the Doctor during the regeneration , clicks uselessly . A scintillating conversation ensues and Melody pulls a banana at the Doctor , who had turned the fruit bowl she had left the gun in , then Melody swings a letter opener at him but is disarmed . The Doctor asks why she didn ' t kill him in the field and receives the reply that they ' d only just met — she ' s a psychopath , not rude . An impatient Melody asks if killing him will take all day . The Doctor inquires if she was busy and , an explanation that the Silence tailored Melody as the Doctor ' s " own bespoke psychopath " later , Melody kiss es him with poisoned lipstick and jumps out a window to go shopping . The Doctor gives Amy his sonic screwdriver and tells her to find Melody . Dying , he stumbles into the TARDIS . Outside , Melody enrages soldiers into shooting her . Rory , horrified , cries out , " No ! " as his daughter is pelted by automatic gunfire . However , she is within the first fifteen hours of her regeneration ; she produces a shock wave that heals her and knocks out the guards . She steals a motorcycle . Amy and Rory steal another and follow her . Inside the TARDIS , the Doctor turns on the voice interface as a hologram of himself . He asks for someone he likes . In succession , it offers images of Rose Tyler , Martha Jones and Donna Noble , all of whom induce wails of guilt . Finally , it offers young Amelia Pond , who tells the Doctor that he will shortly be dead . The poison comes from the Judas tree , and regeneration is not available . The Doctor tries to get " Amelia " to help him gather his strength . It insists it is not Amelia , but a hologram . He collapses , gasping for help , then hears Amelia the hologram say " Fish fingers and custard " . He finds the strength to drag himself to the console . Elsewhere , Melody enters a restaurant and orders the patrons at gunpoint to take off their clothes . Outside , Amy and Rory wonder where she is . They see the screaming restaurant patrons run out in their undergarments and hurry in just as the " Teselecta " , now in Amy ' s form , arrives . Melody is working on her ensemble when Amy — actually the " Teselecta " — runs in . Amy and Rory wake up where the Nazi officer did . They are threatened politely by the antibodies until a crew member gives wrist devices to ward them off . They are taken to the bridge , where they are told that their memories of these events will be erased later . Outside , the " Teselecta " asks Melody why she killed the Doctor on behalf of the Silence . Melody really doesn ' t know . Her past is all a blur . It captures Melody as it did Hitler . The Doctor arrives in evening clothes . He asks whom she killed . He uses a sonic cane to scan the " Teselecta " and learns Amy and Rory are inside it . Melody tries to flee , but is recaptured . The Doctor demands they leave her alone and asks who they are . The " Teselecta " explains that as a form of justice , they visit unpunished criminals at the ends of their lives and " give them hell " , agonising pain , while the timeline continues . The Doctor asks who wants him dead and Amy persuades the captain to tell him . It says the Silence are behind the plot to kill him . They are a religious cult who believe " silence will fall " when the oldest question in the universe is asked . It does not know what the question is . The " Teselecta " resumes torturing Melody . The Doctor tells Amy to save her daughter . She uses the sonic screwdriver to turn off the crew ' s security clearances . The antibodies attack them and they teleport to safety . Amy uses a microphone to ask the Doctor for help . The antibodies are politely threatening Rory and her again . The Doctor struggles against his painful death . He crawls towards the TARDIS , shocking Melody that he still cares . The Doctor asks for her help , using her name , River . Melody demands to know who River is . Inside the " Teselecta " , Amy and Rory are cornered by the antibodies . They accept their doom . Suddenly , the TARDIS materialises around them . They begin to thank the Doctor . Instead , they find a shaken Melody at the console , saying she flew the TARDIS . It taught her how . They go to the Doctor , but he says there is no way for him to survive . He asks to speak to Melody . He asks her to find River Song , whispers something in her ear and dies . Melody asks who " River Song " is . Amy orders the " Teselecta " to show them . It shifts into the form of Melody ' s current incarnation . Melody learned that " she " is River Song . Amy and Rory ask Melody what the Doctor whispered in her ear . She does not answer this , but asks her parents if the Doctor is " worth it " . They don ' t understand her question , but agree he is . Melody kiss es the Doctor and gives up all her regenerations to save him . Melody wakes in the greatest hospital in the universe . The Doctor leaves her a TARDIS blue diary . They must leave her to find her own way back to them . In 5123 , Melody , now calling herself River Song , applies to study at the Luna University . When asked why she wants a degree in archaeology , she says she is " looking for a good man " . The first BBC America broadcast of the episode includes an extra scene which aired during a commercial break . It was sponsored by AT & T . As written by Steven Moffat , it is an extension of the motorcycle chase sequence with Rory and Amy . It is presented in animation / motion comic format . Lasting sixty seconds and produced by Double Barrel Motion Labs , the scene was originally promoted as intended for inclusion in the Series 6 DVD / Blu - ray releases , but as of early November 2011 , this has not happened . The ad / motion comic was only seen in America . Home video releases . This episode , along with the rest of the second half of series 6 , was released on DVD and Blu Ray on the 10 October 2011 . The complete series 6 , which included the first and second half of the series , was released on DVD and Blu Ray on the 21 November 2011 .