Trouble in Paradise ( audio story ) Trouble in Paradise was the sixth release of the " Destiny of the Doctor " audio series , produced by Big Finish Productions for AudioGO . Publisher ' s summary . Responding to a desperate summons from the Doctor ' s future self , he and Peri find themselves on a sailing ship in 1492 , where the crewmen are gripped by superstitious fear . They say the Devil walks among them , stalking and striking them down . Even though they have landed in paradise , they fear that ' El Diablo ' himself will drag them over the edge of the world and into the depths of hell . When the Doctor and Peri meet the captain of the ship , they both discover that heroes can sometimes behave un - heroically . Peri ' s reaction leads her into deep water , and soon the Doctor fears not only for her life but also for the existence of the ship , the paradise island , and the Universe itself . . . Plot . The Eleventh Doctor uses the TARDIS ' s telepathic circuits and viewscreen to contact the Sixth Doctor and Peri Brown . He makes it clear that he is a future incarnation of the Doctor ( with Peri at first reflecting that he is what she would expect from the Doctor ' s son , if he had one ) , and compliments his previous self ; and then he makes a request . He wants the Sixth Doctor to obtain an omniparadox , a most dangerous item . After he leaves , the Sixth Doctor explains that an omniparadox is a sort of power cell , created by the conflict between two versions of time , much as nuclear power is created by smashing atoms together . The omniparadox , however , possesses energies that , if misapplied , can destroy the universe . The Doctor constructs a device to track the signal of an omniparadox ; it does so by mimicking the signal to create a resonance . Tracking , they land aboard a ship — not a spaceship , but a sailing ship — and find the paradox hovering above the TARDIS . However , they are quickly captured by a most unlikely man and his crew , and find that they are in the presence of the famed Christopher Columbus , aboard the " Santa Maria " ; and he has just sighted land . He assumes they are natives of the island he has discovered , and that they have somehow come aboard to worship the invading Europeans . ( The fact that he can converse with them without trouble seems to be lost on him . ) The misunderstandings are interrupted , however , when it is revealed that a man on board is dying — and claims to have seen the devil . Unfortunately , Peri has seen it too , albeit briefly . The Doctor gives her the TARDIS key to fetch a medical kit ; and en route , she sees a demonic creature in the shadows for a moment . The Doctor determines that the man is dying of tuberculosis ; he has the ability to cure him , but refuses to do so , as introducing modern medicine to the year 1492 could be disastrous . Enraged at him , Peri runs off through the hold where the TARDIS is parked , stopping only to throw the key at the Doctor . Peri comes to the prow , intending to just stand there and think , but falls overboard . The Doctor panics , and tries to enter the TARDIS to save her , but cannot find the key . He is diverted , however , when he sees that the omniparadox is now gone ; and shortly thereafter , the universe begins to violently unravel . The Doctor realises that something has caused the paradox to be removed , which means that the Eleventh Doctor ' s mission in the future will fail , bringing about this destruction ; but he stabilizes the situation briefly with his tracking unit , using its false signal to " trick " the universe into stability . It will not last , however , and he has about an hour before things fall apart . Columbus , having had his beliefs challenged repeatedly , now believes the Doctor is a wizard , and orders him to find the key and fix the situation ; if he does not do so in twenty minutes , Columbus will cut off his hands , a punishment that history attests he used often on the native populations . Peri , meanwhile , is not dead . She finds herself washed up on the shore — and is immediately captured by natives who are under the control of a monster . The monster is the devilish figure she saw ; it confronts her , and reveals itself to be the Herd Leader of the Bovine race , a race of intelligent buffalo . Once they ruled the continent , and the primitive humans worshipped them ; but then the herd leader was trapped in ice . Without its mind , the herd regressed into common buffalo , and were hunted to extinction . In the future , when the herd leader thawed out , he found he had no herd to lead . Adopting time travel technology which had since been developed by humans , he travelled back to conduct experiments which would save his people . He believes that Peri and the Doctor were sent to stop him . The Doctor determines that a goat in the hold has eaten the key . However , he retains a psychic connection to it ; and he is able to telepathically connect it to the TARDIS despite the goat ( and much to the goat ' s alarm ) and get the door to unlock . With Columbus in tow , he determines that Peri is alive , and travels to her location ; unknown to him , Columbus — now convinced the Doctor is a superior explorer — plans to kill him out of jealousy . Arriving at the Herd Leader ' s time machine , they learn its plan . It was the herd leader that led Columbus to the new world — Columbus being an incompetent navigator on his own — in hopes that the Europeans will exterminate the native Americans , thus preventing them from exterminating the Bovine herd . In that way he can return to the future and resume his place as herd leader . They are shocked to see another Herd Leader appear and interrupt , however ; or rather , the same one , but older . The second leader says he is from the future , and has come to stop the experiment , because it will be a failure — the Europeans , too , will hunt and control the Bovine . The Doctor uses this opportunity to surreptitiously remove the time element from the machine . Warned by Peri , he dodges out of the way as Columbus tries to kill him with a sword ; Columbus misses and destroys the time element by accident . The second herd leader vanishes , being unable to have time - travelled without the machine ; the first is forced to flee . After removing the time machine , the Doctor , Peri , and Columbus return to the ship . Columbus is forced to acknowledge that the Doctor and Peri are not natives after all ; this does not change his plans , but he debates recording these events . He sends his men ashore to hunt down and kill the herd leader , convincing them it is not a devil , but an animal . The Doctor sees that the omniparadox has returned , and collects it ; he theorises that it disappeared because of the likelihood of Peri ' s death . Without her to warn him of Columbus ' s strike , the timeline would have been vastly different ; and it was the collision of the timelines of the two herd leaders that created the paradox in the first place . Having a final change of heart , he cures the man with tuberculosis , and then they depart .