Day of the Triffids is so classic it is almost cliche. The book is predicated on cold war paranoia and middle-class fears. Wyndham makes allusions to communism in the single-minded Triffids who act with a single intent, destruction and consumption of humans, with callous disregard for individuals of its own species.
Some foreign country designs a new type of plant, the triffid, as a weapon of economic warfare. However, the plant is spread when an attempt to steal a box of seeds goes wrong, allowing the almost weightless seeds to spread all over the world. The new plant has some disturbing behaviours. A mature plant is capable of stinging and blinding a human; the plant is carnivorous; the plants are capable of moving, especially over dirt but they can cross pavement for short distances if necessary; the plants are intelligent and probably have a means of communicating to each other through vibration.
A possibly-unrelated meteor shower blinds any human who gazes at it, rendering humanity helpless. The Triffids take the opportunity to break free of their prison-farms and attack the newly blind. Attempts to gather, protect and repopulate humanity quickly go awry. Our protagonist carves out a small niche in a farm, batteling the Triffids and attempting to creat self-sufficiency. Eventually, they face the option of joining a more survivors on the Isle of Wight where the Triffids have been prevented from taking root literally or giving in to a fascist military organization.
If I seem dismissive about the plot, please forgive me. It was an original that has been used, manipulated, borrowed and stolen so it is as familiar as peanut butter. The story takes place in the middle of events, the day after the meteor shower, while the protagonist is healing from a Triffid sting. It similarly ends in a transition as the farm community strikes out to cast their lot on the island. Struggle and doubt are felt the entire plot length; they are never resolved. It's a lot like life - blind people groping about to survive, trusting those who claim to see, petty fighting, constant threat, uncertaintity, etc.
There are four failed attempts to (re)establish society: 1-A society repopulated by seeing men procreating with numerous, mostly blind-from-birth women. This experiment is aborted before it is even tested. It is met with some resistance because it goes against current mores and because it fails to provide for those who are newly blind.
2-A second attempt forces the seeing to be shackled into slavery to save the blind by scavenging for food. The seeing person is handcuffed to one or two blind persons so he can not simply escape. Their lives are spend searching for increasingly depleted food sources. Eventually, a strange disease, possibly food poisoning, begins to work its way through the blind, and possibly other people who can see.
3-A third society is created by one of the dissidants in the first group. She creates an impractical and overly idealist religious colony based upon Christian morals, or at least her interpretation of them. While this society temporarily functions, it fails to provide adequately for the future and the threat of Triffids.
4-The final attempt is the small farm tribal self-sustaining farm that faces increasing threat from the Triffids. This little society tries to fence out the world and Triffids but cannot continue to defend itself from either.
The fifth society is not reached. It is created by the original leader of the first movement but with some practical modifications.