The Four Doctors ( audio story ) The Four Doctors was the eighth subscriber - exclusive release from Big Finish . It featured the Fifth , Sixth , Seventh and Eighth Doctor s , played by all the actors who played the Doctor with whom Big Finish then worked . Publisher ' s summary . The fifth incarnation of the Doctor has been allowed access to the Vault of Stellar Curios , where the biomechanoid Jariden are at least prepared to consider his warnings about dangerous temporal leakage . Suddenly , out of nowhere , the Dalek s attack , unleashing a temporal maelstrom that will not only threaten the Jariden race , but will have dire consequences for the history of the Doctor himself . Plot . Travelling through the Time Vortex , the TARDIS detects a leak of chronon particles , which are causing temporal distortion s in local space . The Fifth Doctor believes that it is being caused by whatever is stored in the inner vault of the Jariden Vault of Stellar Curios . At the vault , he speaks to Professor Kalinda Ulrik , the facility director . According to Kalinda , the Fifth Doctor is fully versed in every detail of the Vault of Stellar Curios ' top secret temporal research . Kalinda ' s elder brother Colonel Ulrik arrives in the Vault in order to conduct a military inspection . Their grandfather , who is long dead , had fought in the Jariden war against the Dalek s decades earlier . A Dalek assault vessel , which is under the command of the Dalek Prime , is on its way to the Vault , looking for its mysterious contents . The Eighth Doctor ' s TARDIS materialises in the Vault , intending to land at the Petrachi Collection . He recalls his fifth incarnation ' s encounter with Kalinda , but does not immediately recognise her . His TARDIS likewise detected the emission of chronon particles . Colonel Ulrik is collaborating with the Daleks and has deactivated the station ' s defence shields . Ulrik forged a deal with the Daleks to allow them to have the contents of the inner vault on the condition that they withdraw from Jariden space immediately . The Eighth Doctor tells Kalinda that he was present at the Battle of Pejorica in a " former life . " By wiring Kalinda ' s personal communicator into the station ' s communications system , the Eighth Doctor contacts his fifth incarnation in the laboratory wing . He claims that he is a Time Lord agent working on behalf of the High Council . The Fifth Doctor intends to use a light comb generator to create a highly localised disturbance in space time . The Eighth Doctor tells him that this will create a temporal whirlwind and that he must contain the temporal instability . He has Kalinda instruct his younger self to create a time loop to contain the Daleks by forming a temporal bridge between their two TARDISes . Colonel Ulrik is sent back through time to the laboratory of Professor Michael Faraday in the Royal Institution in London in 1854 . The inoperative Special Weapons Dalek arrived in the lab one week earlier . Colonel Ulrik describes 19th century Earth as possessing sub - Level 4 technology . Shortly after Ulrik ' s arrival , the Seventh Doctor ' s TARDIS materialises in Faraday ' s home , which contains one end of an unstable time - space corridor that he intends on sealing to prevent anything else from falling through it . On being introduced to Ulrik , the Seventh Doctor tells Faraday that they have already met . Before the Seventh Doctor can seal the time - space corridor , however , two more fully active Daleks , one of whom is the Dalek Prime , arrive Faraday ' s house . The Daleks recognise the Doctor in his seventh incarnation . After activating Faraday ' s electromagnet , which disrupts the two Daleks ' functioning , the Seventh Doctor is able to escape through the dumbwaiter . The Seventh Doctor tells Ulrik that they have actually met on two previous occasions : the first was in the Vault while the second was on the battlefield of Pejorica on the planet Sovavevanti . Colonel Ulrik is swept through the time corridor and arrive in Pejorica during the battle . He is captured and tortured by the Daleks of that era . Ulrik is revealed to be a functional upgrade of the Jaridens who fought in the Battle of Pejorica . His technology is unknown to the Daleks . He serves in the 47th Division of the Jariden Army , his ident number being C - Four - Alpha - Z . While in his cell , Ulrik converses with the Sixth Doctor , telling him that he arrived in the midst of the Battle of Pejorica , the Jaridens ' " glorious , historic victory over the Daleks . " Ulrik tells the Sixth Doctor that it seemed anything but glorious . He sought refuge in the manor house to which his grandfather had fled but discovered that it was being used as the Dalek base of operations in Pejorica . The Battle of Pejorica occurred at a point in Dalek history prior to the creation of the Dalek Prime and the Special Weapons Dalek . The Sixth Doctor believes that the two future Daleks were captured by the Jariden forces , reverse engineered and used to create the next generation of Dalek technology . However , Ulrik learns that this was only true of the Special Weapons Dalek as the Dalek Prime was eventually able to assume command of the past versions of the Daleks . Ulrik determines that he and the Dalek Prime are not travelling back along their own timelines but that of the Doctor . Kalinda and Ulrik ' s grandfather did not flee the Battle of Pejorica as they were brought up to believe but was captured by the Daleks and converted into a Roboman . As per the Sixth Doctor ' s instructions , Ulrik liberates his robotised grandfather from Dalek control and instructs him to surrender himself to the Jariden forces . When Ulrik comes within range of the time field generated by the TARDIS , the residual chronon particles cause him to be sent forward in time to the Vault , which was his initial starting point . While the Sixth Doctor had hoped that the same would be true of the Dalek Prime , it instead remained in Pejorica , poised to exterminate him . In the Vault several decades in the future , Magran tells the Fifth Doctor that the defence shields have been deactivated and that a Dalek assault vessel is approaching . It soon boards the station . The Fifth Doctor , Magran and several other scientists barricade themselves inside the laboratory wing of the Vault . According to Magran , the inner vault contains a device which is the work of generations of Jaridens . The Fifth Doctor tells Ulrik that he intends to use the light comb generator to create a highly localised disturbance in space - time . Shortly afterwards , the older Ulrik arrives in the laboratory through such a disturbance . The older Ulrik incapacitates his younger self , which he recalls happening to him earlier in his personal timeline . The Fifth Doctor receives a message from a Time Lord agent who is working for the High Council . He intends to use a light comb generator to create a highly localised disturbance in space time . The Time Lord agent tells him that this will create a temporal whirlwind and that he must contain the temporal instability . As per the instructions of the Time Lord agent , Kalinda suggests that the Fifth Doctor create a time loop to contain the Daleks by forming a temporal bridge between his TARDIS and that of the Time Lord agent . The Fifth Doctor determines that the Time Lord agent is , in fact , his future self , given that the older Ulrik had told him that he had travelled along his personal timeline and met three of his other incarnations . The Vault contains the still robotised version of Ulrik ' s grandfather , who has been fused with the remnants of the Special Weapons Dalek which the Jariden forces procured at the Battle of Pejorica . The older Ulrik instructs his grandfather to destroy the Daleks but they are exterminated before this can occur . The younger Ulrik sees the corpse of his future self shortly before he , the Dalek Prime , the younger version of the Special Weapons Dalek and another Dalek are sent back in time to 1854 . Shortly before the Eighth Doctor and Kalinda are going to exterminated , the remaining Daleks vanish due to the resonating TARDIS trace pulling them into the Time Vortex . He tells her that he has seen this happen before , specifically on Sovavevanti during his sixth incarnation and in London in 1854 during his seventh incarnation . The Eighth Doctor enters the TARDIS to find that his fifth , sixth and seventh incarnations are all present due to the temporal instability . The time phasing eventually corrects itself and the younger Doctors are returned to their own versions of the TARDIS at the proper points in their respective personal timelines . The Eighth Doctor is the only one of the four of them to remember their encounter in the TARDIS .