After meteors enter Earth's atmosphere, blinding much of the planet's population in the process, plantlike creatures known as Triffids emerge from the craters and begin to take over. Military officer Bill Masen (Howard Keel), one of the few sighted people left alive, meets with other survivors in England and tries to find a safe haven from the vicious vegetation, as scientist Tom Goodwin (Kieron Moore) desperately seeks a way to defeat the leafy extraterrestrials.