The Night of the Triffids

At the end of The Day of the Triffids the hero Bill Masen his wife and four-year-old son leave the British mainland to join a new colony on the Isle of Wight. The Night of the Triffids takes up the story 25 years later. David Masen the now grown-up son of Bill is a pilot still searching for a method of destroying the implacable triffid plant as it continues its worldwide march seemingly intent on wiping out humankind. David eventually manages to reach New York where a very different sort of colony has been set up a colony whose members seem to be immune to the triffid string and where David comes face to face with an old enemy from his fathers past.