|The Four Doctors|
|Main enemy:||The Daleks|
|Main setting:||The Vault of Stellar Curios|
|Release date:||December 2010|
Specially Released Audio Dramas
|An Earthly Child||The Five Companions|
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 Daleks 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.
The Fifth Doctor investigates the Vault of Stellar Curios, where he has observed evidence of time leakage. But then the Daleks attack, looking for the contents of the mysterious vault. The Eighth Doctor also shows up and he and his former self create a time loop trap, spanning between their lives. This sends the Daleks to the Seventh Doctor's encounter with Michael Faraday in 1854 and the Sixth Doctor's visit to an early Dalek battlefield.
- The Doctor - Peter Davison
- The Doctor - Colin Baker
- The Doctor - Sylvester McCoy
- The Doctor - Paul McGann
- Professor Kalinda / Lady Cowen - Ellie Burrow
- Colonel Ulrik / Whitmore - David Bamber
- Professor Michael Faraday / Magran - Nigel Lambert
- Roboman / Jariden Device - Alex Mallinson
- Voice of the Daleks - Nicholas Briggs
- Professor Kalinda Ulrik is the facility director of the Jariden Vault of Stellar Curios.
- According to Kalinda, the Fifth Doctor is fully versed in every detail of the Vault of Stellar Curios' top secret temporal research. While travelling through the Time Vortex, the TARDIS detected dangerous levels of chronon particles, which are causing temporal distortions in local space. The Fifth Doctor believes that it is being caused by whatever is stored in the inner vault.
- Kalinda's elder brother Colonel Ulrik arrives in the Vault in order to conduct a military inspection. Colonel Ulrik refers to her as "little sister." Their grandfather, who is long dead, fought in the Jariden war against the Daleks decades earlier.
- A Dalek assault vessel, which is under the command of the Dalek Prime, is on its way to the Vault.
- The Jaridens are a race of biomechanoids.
- When his TARDIS materialises in the Vault, the Eighth Doctor's intended destination was the Petrachi Collection. He recalls his fifth incarnation's encounter with Kalinda, which occurred many years earlier in his personal timeline, but does not immediately recognise her. His TARDIS likewise detected the emission of chronon particles.
- The Eighth Doctor describes the Fifth Doctor as "a blond chap in Edwardian cricket gear" who is "terribly polite." He claims that he is his younger self's superior.
- 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 a functional upgrade of the Jaridens who fought in the Battle of Pejorica. His technology is unknown to the Daleks.
- Ulrik serves in the 47th Division of the Jariden Army. His ident number is 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 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.
- 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.
- 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.
- When the Sixth Doctor criticises the design of the Eighth Doctor's console room, his future self comments that his sixth incarnation should not be the one giving tips on interior decorating, referring to his mult-coloured coat.
- The Seventh Doctor determines that the Eighth Doctor is "the latest model" as he is the only one whom he does not recognise.
- This is a special release given away to Big Finish subscribers who had AUDIO: The Demons of Red Lodge and Other Stories as part of their subscription.
- The audio is accompanied by a commemorative sixteen-page booklet.
- The character names "Lady Cowen" and "Whitmore" are in-joke references to two friends of the author, Laura Cowen and Tony Whitmore.
- This is the first performed multi-Doctor story to feature the Daleks, excluding their brief appearance in TV: The Five Doctors.
- Along with AUDIO: Zagreus and AUDIO: The Light at the End, this is one of only two Big Finish audio dramas in which Peter Davison, Colin Baker, Sylvester McCoy and Paul McGann all appear. Tom Baker appeared with them in The Light at the End. Furthermore, Davison, Colin Baker and McCoy all appeared in AUDIO: The Sirens of Time, Colin Baker and McCoy also appear in AUDIO: Project: Lazarus, AUDIO: The Wormery and AUDIO: Thicker than Water together while both McCoy and McGann appear in AUDIO: Klein's Story.
- The Dalek Prime is in command of the Dalek assault vessel which boards the Vault of Stellar Curios (PROSE: War of the Daleks) while a Special Weapons Dalek is among the Dalek forces (TV: Remembrance of the Daleks). Both are sent back in time to the home of Professor Michael Faraday in London in 1854.
- The Daleks used Robomen during the Battle of Pejorica. (TV: The Dalek Invasion of Earth)
- The Fifth, Sixth and Seventh Doctors all previously met each other in AUDIO: The Sirens of Time. The Fifth and Sixth Doctors also met each other in AUDIO: Peri and the Piscon Paradox. On that occasion, the Sixth Doctor disguised himself as a Piscon named Zarl so his younger self did not realise his identity. The Fifth and Seventh Doctors also met on at least two other occasions, namely in PROSE: Cold Fusion and prior to the events of AUDIO: The Veiled Leopard. Furthermore, the Eighth Doctor previously met his three immediate predecessors (as well as his first four incarnations) in PROSE: The Eight Doctors. Given that the Seventh Doctor failed to recognise his immediate successor on this occasion, it is logical to assume that none of the first seven Doctors retained any memory of meeting their future self.
- The Eighth Doctor remembers speaking to the Fifth Doctor over the intercom from the perspective of his younger self as well as other details of his fifth incarnation's visit to the Vault of Stellar Curios such as meeting Kalinda. This is similar to AUDIO: Peri and the Piscon Paradox, PROSE: Cold Fusion and TV: Time Crash in which the Sixth, Seventh and Tenth Doctors respectively remember the events portrayed from the point of view of their fifth incarnation.
- The Seventh Doctor previously visited 1854 when he and his companions Ace and Hex travelled to Scutari and Sebastopol in September of that year during the Crimean War (1853-1856). (AUDIO: The Angel of Scutari)
- The Seventh Doctor fails to recognise his immediate successor. However, during his sixth incarnation, he along with his companion Evelyn Smythe observed two Eighth Doctors, Charley Pollard, C'rizz and Lucie Miller meeting in an American frontier town in the 1870s. (AUDIO: The 100 Days of the Doctor)
- The Four Doctors at the Doctor Who Reference Guide
- DisContinuity for The Four Doctors at Tetrapyriarbus - The DisContinuity Guide