The Day of the Triffids is a 1951 science fiction novel by John Wyndham, arguably the most famous of the British author's so-called "cosy catastrophes".The book's narrator is an Englishman named Bill Masen, who details how some years previously the eponymous carnivorous plants mysteriously began to appear all over the world, eventually proving to be capable of movement and possessing the ability to attack humans with their poisonous stings; Masen's own theory is that they were deliberately bioengineered in the Soviet Union and then accidentally released into the wild, but the truth is never revealed. Whatever their origin, the plants are also discovered to produce a high-quality vegetable oil, and so an entire industry grows up around farming them. Masen works as a researcher on a Triffid farm, and ends up in the hospital after a Triffid stings him on the face. His eyes thus bandaged, he misses a bizarre meteor shower that lights up the night skies all over the world. Come morning, Masen learns that the shower has struck blind everyone who viewed it. (He later speculates that the shower was actually a malfunctioning orbital weapons system, but again no proof is to be found one way or the other.) Wandering through a disintegrating London, he meets and quickly falls in love with a sighted novelist named Josella Playton (who missed seeing the "meteor shower" because she was sleeping off an unfortunate party experience.) While the Triffids rapidly break free of their farms and begin wiping out the blinded population, Masen and Playton become entangled in the squabbles of other sighted survivors leading to their unwilling separation. They are finally reunited at a small estate in the English countryside, taking up farming in an fenced enclave surrounded by hordes of Triffids. When a despotic new government appears on the scene, they join a colony of more freedom-minded individuals on the Isle of Wight, researching for the day they can defeat the Triffids and reclaim the Earth for humanity.In 2001, the author Simon Clark wrote a sequel to the book entitled Night of the Triffids, which attempted to be a pastiche of Wyndham's style, and details the adventures of Bill and Josella's son.The novel has been adapted for film three times, the first being a loosely-adapted 1962 feature film, the second a 1981 BBC miniseries which, while low-budget, is quite faithful to the original work, and then once more by the BBC in 2009; again the plot deviated a great deal from the original.
Baby Factory: one of the most horrifying aspects of the plot's entire setup is that they cannot possibly help the vast majority of the population, who have been blinded. Eventually even the "Good" faction of people led by Beadley grudgingly concludes that all of the blinded men are a drain on resources and thus a complete write-off. Conversely, Beadley's openly stated position - grudgingly accepted even by the protagonist - is that blind women of childbearing age will be kept alive and in polygamous relationships with the remaining sighted men, to try to repopulate as quickly as possible.
Both Sides Have a Point: Bill Masen is initially somewhat shocked at the pragmatic abandonment of most of the blind population in London by Beadley and the Institute group and sympathizes with Coker's more idealistic attempt to help them. Ultimately, he comes around to the Beadley position when Reality Ensues.
Evil Redhead: Torrence is first seen casually firing on Bill's blind group so they won't compete for resources. When we next see him he's posing as a member of a restored government (actually a feudal military dictatorship).
It Can Think: The exact level of intelligence of the genetically-engineered triffids is a subject for debate, with the protagonist rubbishing the idea that they're intelligent —- after all, dissections haven't found anything remotely like a brain. Others are not so sure. One man points out that the triffids escaped from their farms within hours of everyone going blind. In another scene a triffid is waiting outside the very door which a person would run out of if they heard someone driving down the road. Much like the Velociraptors in Jurassic Park, they're also smart enough to avoid an electrified fence...and to force it down when the electrical power is off. They even have a crude form of communication by drumming their branches against their trunk, though whether this is a crude but effective "hunting call", or an actual complex "language" is unknown. Overall, they seem to have at least the same basic intelligence level as a pack of dogs.
Just Think of the Potential: Used both positively and negatively; the money to be made from the Triffids' oil, while pre-disaster one of Masen's colleagues speculates about Triffids' advantages over a blinded human.
Kill It with Fire: Flamethrowers prove to be the most effective anti-Triffid weapon, although a lack of fuel is a major problem.
Missing the Good Stuff: Masen initially feels hs way about being blindfolded during the spectacular meteor shower. Soon enough, of course, he comes to realize what a lucky break it actually was.
Never Live It Down: invoked Josella and her "scandalous" novel Sex Is My Adventure. The 1981 adaptation, being made in much less straitlaced times, quite sensibly dropped this aspect.
No FEMA Response: A plot point. The first third of the book and the original TV adaptation is driven by the conflict between one faction of sighted survivors who are desperately trying to hold things together until an official relief effort of some sort arrives, and another group who have concluded that there isn't going to be one and they should salvage what they can and get out while the going is good. The second group turns out to be right, and the desperate attempts to keep hundreds of blinded and near-helpless people alive were all for nothing. Being a Cosy Catastrophe doesn't stop this book being pretty bleak in places.
Reality Ensues: One of the greatest and earliest examples of this trope in apocalyptic literature. The author takes the general "survive the Zombie Apocalypse" horror story (using plants instead of zombies or nuclear war), and extends it forward for several years. Quite simply...scavenging for canned food in the ruins of major cities is not a viable survival strategy on a long time scale. Crowds of blind people scavenge in the early days, but there's a finite supply of canned food and they run out eventually. Nor do the more lucky survivors simply flee to a pastoral existence raising their own crops in the countryside. The author repeatedly underlines the point that even those who survived long enough to plow their own fields, need to learn how to forge their own iron to make their own plows. If they're just scavenging old plows, they're not much better than the blind people scrabbling for cans in ruined shops. The entire set of interconnected relationships that are required for civilization are needed for long-term survival.
Soviet Superscience: Bill Masen speculates this might have been the origin of the triffids. However, he can only develop this story through several signs about things he learned during his work with the triffids.
The Great Politics Mess-Up: Averted in the book, kind of; Wyndham liked to throw in a bit of exposition about the Soviet Union for the benefit of future generations too young to recall the Cold War. Illustrated neatly by a scene in the first chapter when a shady individual claiming he can supply triffid seeds to a British firm points out that dealing with the suppliers directly might be difficult; in the book, this is the cue to pause the action for about half a page of exposition. In the 1981 TV adaptation, the company executive sums it up with one sentence:
Zombie Apocalypse: Triffids aren't undead humanoids, but in terms of behavior and threat level they share more than a passing resemblance.
Zombie Gait: The blind, who are shuffling around mindlessly pawing at things and wailing — they were sighted a few hours ago and with no experience in living without it or anyone to help, they're stumbling around in the dark. Possibly leads to Unfortunate Implications if it looks as if only sighted people can possibly think of ideas about working together. Subverted towards the end of the book by the original inhabitants of the farmhouse.
Again, the Triffids themselves lurch slowly about using their three "legs".
Examples specific to Simon Clark's sequel:
Acquired Poison Immunity: the revelation of how humanity can take Earth back from the triffids. Small doses of triffid venom, combined with eating triffids, can help immunize people from the venom.
Baby Factory: a non-enforced version appears in the Isle of Wight, where blind and sighted women live in great houses together, having children with any man they choose, and taking care of the children communally. The New York community has women basically treated as slaves, forced to have many multiple pregnancies.
Big Applesauce: seems to be an utopian community, protected from triffids thanks to blocked bridges. The utopia part is a lie: there is a segregation system between white sighted people and the rest and slavery runs rampant in northern Manhattan (where factories manned by blind people, those who made the mistake of complaining about the system and those who are too weak run 24/7) and some other places (where the workers are forced to work non-stop to cut trees for ethanol or to mine coal) and many women are forced to become a Baby Factory. Being the child of New York's leader won't save you, and in fact he will send you to that destiny because of his relation to you.
Call Back: the beginning is a call back to the beginning of the original novel: both characters wake up unable to see anything, and think that when the situation is similar to what is going on then, something very bad is happening.
Chekhov's Gunman: General Fielding, the leader of the New York community in the sequel, is mentioned about still having some red hair amongst the white hair, and a blind eye from being hit there by a triffid. He is actually Torrence, the Big Bad of the first book, who managed to survive the triffids' attack at the end of the first book.
Foreshadowing: David finding Christine alive in the floating triffid island despite the fact that she has probably been living with triffids for most of her life. It is the signal that people can become immune to the venom.
Irony: Bill Masen comments with David about the irony of triffids being both their greatest enemy and their greatest source of fuel.
Torrence, who hates blind people and the Masen for their role in leaving him half-blind, is finally toppled thanks to a march by blind people whose children are soldiers, and ends up being blinded by David Masen.
La Résistance: a group with bases somewhere in the East Coast and in the Great Lakes is opposed to the semi-fascistic New York regime.
Medieval Stasis: Bill Masen tells David that the Isle of Wight community has hardly changed in the thirty years since it was established, and that, apart from a few things, the only thing they are able to do is to restore old things. He predicts their community will die if something is not done soon.
Nothing Is Scarier: at the start of the novel, it is completely dark, and David only has a lamp without mirrors to see the path. He can't see the triffids, which adds to his nerves.
Sequel Hook: at the end of the novel, a transmission is detected from somewhere else in the world, and an expedition is announced to find those people.
The Night That Never Ends: the novel begins at 9 AM in summer, and when the main character awakens it is as dark as midnight in winter. A combination of very dense clouds and an asteroid cloud passing between the Sun and Earth is the cause. Later in the story, when the clouds leave, there is light, but the sun looks like it is dying.
Universal Poison: the triffid venom is shown not to be this. A lecture in the first chapter tells that it is not an instant killer, but the antidote has to be injected into the carotid artery very soon.
Moral Dissonance: Mason returns to the chateau the find sighted convicts holding the blind women at gunpoint and sexually assaulting them. He gets Christine Durrant and Susan into the truck and drives away, making no attempt to save the helpless women. Even Durrant - who earlier had vowed not to abandon the others - never mentions the chateau incident again.
Plant Aliens: As noted, the original didn't establish where they came from (casually speculating on aliens and Soviet Super Science); the movie version explicitly made them into aliens.
Promoted to Love Interest: After Josella was removed from the 1962 movie version for God knows what reason they decided to replace her role in the story with Durrant of all people!
The Charmer: Torrence is a pretty charismatic leader though not quite the ladies' man he fancies himself to be.
Chekhov's Gun: The masks used by the tribesmen in Zaire are not to protect their eyes from Triffids, but are a means of making them immune to their sting. Also Bill's triffid recording makes itself useful on several occasions.
Chess Motifs: Chess pieces on a map of London show the expansion of Torrence's empire.
Gun Accessories: The torches attached to the weapons wielded by Torrence's mooks are fully justified — for those who still have their sight, being able to see an enemy that doesn't use sight is one of the few advantages they have.
Hope Spot: Mason's father develops a Triffid which will produce sterile spores. It gets destroyed in an attempt to free him from its grasp.
Idiot Ball: Mason's father plays a recording of a wild Triffid in a room connected to his captured Triffid's cage. It reacts badly.
The survivors who follow Torrence decide to stay in London. Because an entire city filled with rotting corpses isn't going to cause a lot of outbreak of disease? Or you know, attract a horde of Triffids who eat the dead?!
Kick the Dog: After Jo broadcasts a message warning people about Torrence's reign and does a bunk, Torrence empties his pistol into the guy manning the radio station.
Torrence's first scene where he's awake involves him realizing that everyone else on the place is blind, it's about to crash and then deciding to steal everyone's lifejackets so he can cushion himself from the impact with them.
Suspiciously Apropos Music: Amusingly inverted — Jo and Bill are doing a Dance of Romance after being apart for so long; the music they are dancing to contains the lines: "Mother Nature and me are the best of friends."
Town with a Dark Secret: The convent is protecting itself by sending out expendable members of the community to be eaten by triffids, thereby keeping them docile.
Several shots are almost identical to iconic scenes from 28 Days Later — which itself, while not an official adaptation of tDofT, openly reused several plot-points.
Torrence in the airliner crash is probably a reference to a similar crash in the 1962 movie (though no-one survived that one). Likewise Susan's Sterling submachine gun is a modern version of the Sten gun wielded by Janette Scott in the movie's publicity material.