Peri and the Piscon Paradox (audio story)

 was the seventh release of the fifth series of the Companion Chronicles produced by Big Finish Productions. It was also the first Companion Chronicles release to feature an actor who played the Doctor, with Colin Baker playing his role of the Sixth Doctor. However, Nicola Bryant provides narration as well as the Fifth Doctor's dialogue.

Publisher's summary
The Doctor and Peri journey to Los Angeles 2009 to do battle with a Piscon. His name is Zarl, and he's a fish of utmost evil.

Zarl is going to steal all the water of Earth and sell it to the highest bidder. Or blow up the San Andreas fault. Or the planet. Or something like that. He's a bit vague on that point.

Fortunately, to stop him there’s help from an unexpected source: a future version of Peri. She knows Zarl's dark secret.

But should the future Peri be on Earth at all? Something smells fishy – and it's not just Zarl.

Plot
to be added

Cast

 * Peri Brown - Nicola Bryant
 * Sixth Doctor - Colin Baker
 * Carburetor - Nicola Bryant

Cultural references

 * On seeing her older self for the first time, the young Peri wonders if she is an actress who used to play the Fonz's girlfriend in Happy Days or a "green good time girl" in Star Trek.
 * The older Peri tells her younger self that she is in the employ of a secret government organisation known as the X-Files. The younger Peri, being from 1984, is totally unaware that The X-Files is a science fiction television series from the 1990s and takes her at her word. The Fifth Doctor, however, is familiar with the series. He comments that it was never as good after David Duchovny left. He commends the older Peri for her quick thinking and for not revealing anything to her younger self about her personal future.

Individuals

 * Peri's parents, Janine and Paul Brown, were married on 21 November 1962.
 * Peri's Aunt Mona resembles the Sixth Doctor.

Species

 * The Fifth Doctor refers to the Pescatons, who he claims are more violent than the Piscons. (Doctor Who and the Pescatons)
 * In an attempt to jog the older Peri's memories, the Sixth Doctor mentions Sil, the Tractators, the Ice Warriors and Davros.

Theories and concepts

 * Both the Fifth and Sixth Doctors mention the Blinovitch Limitation Effect.

Continuity

 * The Fifth Doctor refers to the Pescatons. (Doctor Who and the Pescatons)
 * The younger Peri wonders if her mother is still alive in 2009. (BFA: The Reaping)
 * The older Peri claims that the disappearance of the Mary Celeste's crew was caused by Piscons wanting to take over human forms. This was later revealed to be completely made up. In reality, the First Doctor and his companions Ian Chesterton, Barbara Wright and Vicki Pallister were indirectly responsible for their disappearance. (DW: The Chase) However, the Doctor later discovered his own involvement with the crew's disappearance as, earlier in his personal timeline, the Fifth Doctor told Alan Fitzgerald, a student summer intern at the Gogglebox, that he was "sort of" responsible. (BFA: The Gathering)
 * In an attempt to jog the older Peri's memories, the Sixth Doctor mentions Sil (DW: Vengeance on Varos, BFA: Mission to Magnus, DW: Mindwarp), the Tractators (BFA: The Hollows of Time), the Ice Warriors (BFA: Red Dawn, BFA: The Bride of Peladon, BFA: Mission to Magnus) and Davros (DW: Revelation of the Daleks).
 * The Sixth Doctor claims that he has been having difficulty with his memory since his most recent regeneration. This could account for the fact that he did not remember meeting Kathy Chambers for the first time in his personal timeline in Brisbane, Australia in September 2006 while in his fifth incarnation (BFA: The Gathering) when they met for the second time (from his perspective) in Baltimore, Maryland in September 1984 while in his sixth incarnation (BFA: The Reaping).
 * The older Peri remembers her first encounter with the Doctor involving a "robot with an identity crisis", "some religious types" and a "crazy guy with a beard". (DW: Planet of Fire)
 * The Sixth Doctor remembers his previous incarnation and the younger Peri encountering the older version of Peri defeating Zarl in Los Angeles in 2009. This is similar to MA: Cold Fusion in which the Seventh Doctor remembers the events of the novel from the perspective of the Fifth Doctor and uses this knowledge against his younger self.
 * The Sixth Doctor refers to Jamie McCrimmon and Zoe Heriot being returned to their native eras by the Time Lords with no memory of their adventures with his second incarnation, aside from their respective first encounters with him. (DW: The War Games)
 * The unnamed Time Lord states that returning companions to their original time and wiping all knowledge of the Doctor save their first encounter with him is "standard procedure", however to date it is only known to have been done with Zoe, Jamie (maybe) and one of the Peris. If it is standard procedure it's possible that other companions may have also suffered the same fate which might explain the lack of involvement by past companions in modern-day Earth scenarios (especially during the revival series).
 * Though it is not stated directly, the older Peri was presumably returned to Earth at some point after September 1984 in order to maintain the Web of Time. Otherwise, her presence would have affected the events of BFA: The Reaping and, by extension, BFA: The Gathering or perhaps even prevented them from coming to pass.
 * The Seventh Doctor would later visit the Peri serving as princess, who would not forgive him for abandoning her. (BE: Reunion)

For the Fifth Doctor and Young Peri

 * Peri and the Piscon Paradox takes place after PDA: Warmonger
 * Peri and the Piscon Paradox takes place immediately before DW: The Caves of Androzani

For the Sixth Doctor

 * Peri and the Piscon Paradox takes place after BFA: Her Final Flight
 * Peri and the Piscon Paradox takes place before BFA: I.D.

For the older Peri

 * Peri and the Piscon Paradox takes place 25 years after DW: Planet of Fire