History Recap / DoctorWhoS38E6Praxeus

* ShoutOut: The Praxeus victims developing crusts on their skin and exploding into dust is similar to the time-delayed death of an apparent survivor of an alien attack in the final ''Franchise/{{Quatermass}}'' series.

* CreepyCrows: Praxeus is spreading itself across the planet by hijacking the bodies of birds that ingest plastic waste, resulting in murders of infected crows flying around the polluted river in Peru and Suki's lab in Madagascar. Late in the episode, the Doctor and her companions are forced to flee when the infected crows attack the lab to try and stop her developing a cure.

Above the Indian Ocean, British astronaut Adam Lang's Soyuz descent capsule malfunctions suddenly, causing him to go missing. In Peru, travelling vloggers Gabriela and Jamila camp by a beautiful river that has become a polluted dump site, but when Jamila wakes up in the middle of the night, she's suddenly attacked by a bird. When Gabriela wakes up and finds her friend missing and dead birds lying about, she tries to touch the bird... only for Ryan to suddenly turn up and warn her not to do so, picking up the bird's corpse in the process. In the UK, troubled ex-policeman Jake discovers that Adam — his husband — is missing, presumed dead, just before receiving a text message from Adam asking for help and placing him in Hong Kong. When Jake arrives, he tries to kick down the door to the building where Adam apparently is, only to be met by Yaz and Graham, who have seen strange energy readings and have the skeleton keys to enter. In Madagascar, scientist Suki Cheng is annoyed when she is yet again beaten to work by her colleague Amaru, when they are called to help rescue a man floating in the surf by the Doctor. The man, survivor of a missing US submarine, panics about something that got inside the vessel before his body is taken over by white scale-like growths and disintegrates.

* SwappedRoles: Most of Yaz's scenes have her become the Doctor, with Gabriela as her companion.

** When the Doctor discovers that plastics are closely linked to the threat of Praxeus, her first thought is to suspect Auton involvement, but she quickly dismisses that because the Autons aren't bacterial in nature.[[note]]Incidentally, this is also the first time in the new series that the word "Auton" has been used in-episode.[[/note]]

* AudienceSurrogate: The word "pathogen" is a reasonably common one. And while many people will not know its full scientific meaning (given that it's a scientific term that doesn't come up much in daily life, to be fair), the companions are once again clueless to what it means, again done so the Doctor can explain its meaning in more detail to the audience. Especially egregious in Grahams case, who was not only married to a nurse, but also went through cancer treatments and the resulting immunosuppression, ''and'' bare minutes later "knows his way around an IV". Plus he's the oldest of the companions, and that alone should be enough for him to not know what it means unbelievable.

* ChekhovsGun: Jake is trying to kick down a heavy metal door when Yaz and Graham arrive and unlock it with a skeleton key. Inside the building, Yaz and Graham find a flimsier wooden door which is also locked and try to figure out how to bypass it... until Jake lightly pushes Yaz aside and kicks it in.

* NextSundayAD: The Doctor's narration places the story "early in the third decade of the 21st century", suggesting it's at most ten years in the future from the broadcast date.

* NextSundayAD: The Doctor's narration places the story "early in the third decade of the 21st century", suggesting it's at most a year or two in the future from the broadcast date.

The Doctor then notices Adam has grown healthy, proving the antidote worked, and that the ship has organic fuel cells. She realizes the fuel cells can be used to amplify the effects of the antidote and distribute it farther out. The Doctor, Yaz, Ryan, Graham, Jake, Adam, and Gabriela repair the ship and set it to fly into the stratosphere to explode and help destroy Praxeus. They escape the ship, only to find that the autopilot is not working and Jake has stayed behind to guide the ship to its definition. Adam pleads to Jake not to sacrifice himself. Jake points out that he wants to, and must, do more to save the billions of lives on Earth. The Doctor rushes to materialize the TARDIS around Jake, though, saving him the millisecond before the ship explodes.

The Doctor rigs up a way to keep Adam alive within the TARDIS console room, and has the TARDIS make an improved antidote. Adam and Jake share a moment together and nearly reconcile.

The Doctor then notices Adam has grown healthy, proving the antidote worked, and that the ship has organic fuel cells. She realizes the fuel cells can be used to amplify the effects of the antidote and distribute it farther out. The Doctor, Yaz, Ryan, Graham, Jake, Adam, and Gabriela repair the ship and set it to fly into the stratosphere to explode and help destroy Praxeus.

Yaz insists to the Doctor that she needs the translucent alien panel, and has to track the aliens down. Gabriela agrees to stay behind in Hong Kong, also to the Doctor's reluctance. The Doctor agrees to let them go for one hour, while she travels to Madagascar to take care of Adam. Yaz and Gabriela return to the alien lab and try to recover the panel, but find another humanoid in a gas mask. He teleports away. Yaz and Gabriela decide to follow him to what appears to be an alien environment of green lights and plastic waste held together by fishing nets, where they are confronted with the mast of the missing submarine.

In Madagascar, the Doctor and company discovers the growths have spread on Adam's face. The Doctor asks Suki if her lab has enough advanced medical equipment, up to a gene sequencer, and Suki confirms it. The Doctor asks Amaru to stay out in front and watch the birds while she studies the growths and Ryan dissects the bird corpse he brought along, which is full of plastic. Meanwhile, Graham assures Adam he knows how to take care of him with an IV drip, having been through cancer treatment; as they wait outside for Adam to heal, Graham comforts Jake, who reveals he has an inferiority complex from being married to Adam; Jake also hates travelling abroad and is afraid to commit, which is why he wasn't present at Adam's launch. The Doctor finds the growths and the odd behaviour of the birds stem from an alien bacterium which attaches easily to plastics, including microplastics; the natural enzymes of the birds are trying to prevent the alien bacterium from spreading.

The Doctor figures that the bird enzymes can be used to engineer a cure for the disease. But after she's gotten a rudimentary antidote synthesized, Suki reveals herself: she's been researching the disease, called Praxeus, the entire time, and now that a cure has been found, she can take the data. The infected birds attack the lab, killing Amaru outside before heading inside, as per Suki's warning that Praxeus knows when people are trying to cure it and will fight back. Suki teleports away, leaving the Doctor, Graham, Ryan and Jake, hauling along Adam, to run for the TARDIS.

* BaitAndSwitch: Adam is left on the TARDIS with Adam while the Doctor's cure runs its course. The instruments on the TARDIS start beeping and glowing red while Adam appears to be getting worse. A bit later, Jake shows up with Adam, who is fine thanks to the cure.

Above the Indian Ocean, British astronaut Adam Lang's Soyuz descent capsule malfunctions suddenly, causing him to go missing. In Peru, travelling vloggers Gabriela and Jamila camp by a beautiful river that has become a polluted dump site, but when Jamila wakes up in the middle of the night, she's suddenly attacked by a bird. When Gabriela wakes up and finds her friend missing and dead birds lying about, she tries to touch the bird... only for Ryan to suddenly turn up and warn her not to do so, picking up the bird's corpse in the process. In the UK, troubled ex-policeman Jake discovers that Adam — his husband — is missing, presumed dead, just before receiving a text message from Adam asking for help and placing him in Hong Kong. When Jake arrives, he tries to kick down the door to the building where Adam apparently is, only to be met by Yaz and Graham, who have seen strange energy readings and have the skeleton keys to enter. In Madagascar, scientist Suki Cheng is annoyed when she is yet again beaten to work by her colleague Aramu, when they are called to help rescue a man floating in the surf by the Doctor. The man, survivor of a missing US submarine, panics about something that got inside the vessel before his body is taken over by white scale-like growths and disintegrates.

Yaz insists to the Doctor that she needs the translucent alien panel, and has to track the aliens down. Gabriela agrees to stay behind in Hong Kong, also to the Doctor's reluctance. The Doctor agrees to let them go for one hour, while she travels to Madagascar to take care of Adam.

Yaz and Gabriela return to the alien lab and try to recover the panel, but find another humanoid in a gasmask. He teleports away. Yaz and Gabriela decide to follow him to what appears to be an alien environment of green lights and plastic waste held together by fishing nets, where they are confronted with the mast of the missing submarine.

In Madagascar, the Doctor and company discovers the growths have spread on Adam's face. The Doctor asks Suki if her lab has enough advanced medical equipment, up to a gene sequencer, and Suki confirms it. The Doctor asks Amaru to stay out in front and watch the birds while she studies the growths and Ryan dissects the bird corpse he brought along, which is full of plastic. Meanwhile, Graham assures Adam he knows how to take care of him with an IV drip, having been through cancer treatment; as they wait outside for Adam to heal, Graham comforts Jake, who reveals he has an inferiority complex from being married to Adam; Jake also hates traveling abroad and is afraid to commit, which is why he wasn't present at Adam's launch. The Doctor finds the growths and the odd behaviour of the birds stem from an alien bacterium which attaches easily to plastics, including microplastics; the natural enzymes of the birds are trying to prevent the alien bacterium from spreading.

* BreatherEpisode: Another standalone episode with a mostly happy ending (the second in Series 12 after "Nikola Tesla's Night of Terror") kicks off the second half of a StoryArc-heavy season, right on the heels of the wringer that the Doctor was put through in "Fugitive of the Judoon". The {{Cliffhanger}} ending of that episode even suggests that the TARDIS is ''deliberately'' distracting her from her gloom by picking up the signals that lead into this crisis.

Above the Indian Ocean, British astronaut Adam Lang's Soyuz descent capsule malfunctions suddenly, causing him to go missing. In Peru, travelling vloggers Gabriela and Jamila camp by a beautiful river that has become a polluted dump site, but when Jamila wakes up in the middle of the night, she's suddenly attacked by a bird. When Gabriela wakes up and finds her friend missing and dead birds lying about, she tries to touch the bird... only for Ryan to suddenly turn up and warn her not to do so, picking up the bird's corpse in the process. In the UK, troubled ex-policeman Jake discovers that Adam — his husband — is missing, presumed dead, just before receiving a text message from Adam asking for help and placing him in Hong Kong. When Jake arrives, he tries to kick down the door to the building where Adam apparently is, only to be met by Yaz and Graham, who have seen strange energy readings and have the skeleton keys to enter. In Madagascar, scientist Suki Cheng is annoyed when she is yet again beaten to work by her colleague Amaru, when they are called to help rescue a man floating in the surf by the Doctor. The man, survivor of a missing US submarine, panics about something that got inside the vessel before his body is taken over by white scale-like growths and disintegrates.

In Madagascar, the Doctor and company discovers the growths have spread on Adam's face. The Doctor asks Suki if her lab has enough advanced medical equipment, up to a gene sequencer, and Suki confirms it. The Doctor asks Amaru to stay out in front and watch the birds while she studies the growths and Ryan dissects the bird corpse he brought along, which is full of plastic. Meanwhile, Graham assures Adam he knows how to take care of him with an IV drip, having been through cancer treatment; as they wait outside for Adam to heal, Graham comforts Jake, who reveals he has an inferiority complex from being married to Adam; Jake also hates traveling abroad and is afraid to commit, which is why he wasn't present at Adam's launch. The Doctor finds the growths and the odd behavior of the birds stem from an alien bacterium which attaches easily to plastics, including microplastics; the natural enzymes of the birds are trying to prevent the alien bacterium from spreading.

* ActorAllusion: The Doctor [[Series/{{Broadchurch}} runs down a beach toward a (soon to be) dead body.]]

* BadassGay: Jake is a HotBlooded ex- {{Cowboy Cop}} with a penchant for kicking down doors. And even though he spends most of his screen time sick with Praxeus, Adam is an astronaut and TheAce.

** When the Doctor discovers that plastics are closely linked to the threat of Praxeus, her first thought is to suspect Auton involvement, but she quickly dismisses that because the Autons aren't bacterial in nature.

* SwappedRoles: Most of Yaz's scenes has her become the Doctor, with Gabriela as her companion.

* StraightGay: Jake and Adam.

* AudienceSurrogate: The word "pathogen" is a reasonably common one. And while many people will not know its full scientific meaning (given that, to be fair, it's a scientific term that doesn't come up much), the companions are once again completely clueless to what it means, which was, once again, done so the Doctor can explain its meaning in more detail to the audience. Especially egregious for Graham, who was not only married to a nurse but also went through cancer treatments and the resulting immunosuppression, ''and'' bare minutes later "knows his way around an IV".

* RoleReversal: For most of the episode, Yaz becomes the Doctor, with Gabriela as her companion anologue.

Above the Indian Ocean, British astronaut Adam Lang's Soyuz descent capsule malfunctions suddenly, causing him to go missing. In Peru, travelling vloggers Gabriela and Jamila camp by a beautiful river that has become a polluted dump site, but when Jamila wakes up in the middle of the night, she's suddenly attacked by a bird. When Gabriela wakes up and finds her friend missing and dead birds lying about, she tries to touch the bird... only for Ryan to suddenly turn up and warn her not to do so. In the UK, troubled ex-policeman Jake discovers that Adam — his husband — is missing, presumed dead, just before receiving a text message from Adam asking for help and placing him in Hong Kong. When Jake arrives, he tries to kick down the door to the building where Adam apparently is, only to be met by Yaz and Graham, who have seen strange energy readings and have the skeleton keys to enter. In Madagascar, scientist Suki Cheng is annoyed when she is yet again beaten to work by her colleague Aramu, when they are called to help rescue a man floating in the surf by the Doctor. The man, survivor of a missing US submarine, panics about something that got inside the vessel before his body is taken over by white scale-like growths and disintegrates.

Above the Indian Ocean, British astronaut Adam Lang's Soyuz descent capsule malfunctions suddenly, causing him to go missing. In Peru, travelling vloggers Gabriela and Jamila camp by a beautiful river that has become a polluted dump site, but when Jamila wakes up in the middle of the night, she's suddenly attacked by a bird. When Gabriela wakes up and finds her friend missing and dead birds lying about, she tries to touch the bird... only for Ryan to suddenly turn up and warn her not to do so. In the UK, troubled ex-policeman Jake discovers that Adam — his husband — is missing, presumed dead, just before receiving a text message from Adam asking for help and placing him in Hong Kong. When Jake arrives, he tries to kick down the door to the building where Adam apparently is, only to be met by Yaz and Graham, who have the skeleton keys to enter. In Madagascar, scientist Suki Cheng is annoyed when she is yet again beaten to work by her colleague Aramu, when they are called to help rescue a man floating in the surf by the Doctor. The man, survivor of a missing US submarine, panics about something that got inside the vessel before his body is taken over by white scale-like growths and disintegrates.