Construction Engineer Stuart Graff(Charlton Heston) is estranged from his jealously possessive wife, Remy(Ava Gardner), and has an affair with Denise Marshall(Genevi?ve Bujold), the widow of a co-worker. Meanwhile, Remy tries to persuade her father, Sam Royce(Lorne Greene), who is Stuart's employer, to use his influence to stop Stuart from seeing Denise. Rogue policeman Lew Slade(George Kennedy) is suspended from the L.A.P.D. for having punched an obtuse officer from another jurisdiction. Embittered, Slade contemplates quitting the police force. Jody(Marjoe Gortner), a perverted grocery store manager, lusts after Rosa Amici(Victoria Principal), sister of Sal, the assistant to Miles Quade, an aspiring daredevil motor cyclist. The lives of all these people are devastated when a major earthquake rips through Los Angeles and reduces the city to ruins.