When Masen's followers are dying of an unknown disease he attempts to find Josella, but his only lead is an address left behind by Beadley's group. They are each chained to a blind person and assigned to lead a squadron of the blind, collecting food and other supplies, while beset by escaped triffids and rival scavengers. The polygamy implicit in Beadley's scheme appalls some group members, especially the religious Miss Durrant, but before this schism can be dealt with, a man called Wilfred Coker stages a fire at the university and kidnaps a number of sighted individuals, including Bill and Josella.

Intrigued by a single light on top of Senate House in an otherwise darkened city, Bill and Josella discover a group of sighted survivors led by a man named Beadley, who plans to establish a colony in the countryside, and decide to join the group. After unbandaging his eyes he wanders through an anarchic London full of blind inhabitants and later becomes enamored of wealthy novelist Josella Playton, forcibly used as a guide by a blind man. The next morning, he learns that the light from the unusual display has rendered any who watched it completely blind (later in the book, Masen speculates that the 'meteor shower' may have been orbiting weapons, triggered accidentally). During his convalescence he is told of an unexpected green meteor shower. The narrative begins with Bill Masen in hospital, his eyes bandaged after having been splashed with triffid poison. The result is worldwide cultivation of triffids. Due to his background, Masen suspects they were bioengineered in the USSR and accidentally released into the wild. The protagonist is Bill Masen, a biologist who has made his living working with triffids – tall, venomous carnivorous plants capable of locomotion and communication, whose extracts are superior to fish or vegetable oils.

The day of the triffids 1951