Last Woman on Earth (1960)

Stars: Betsy Jones-Moreland, Antony Carbone, Robert Towne
Director: Roger Corman
Screenplay: Robert Towne

While vacationing in Puerto Rico, a woman, her husband and their lawyer friend gradually conclude that an unexplained, temporary interruption of oxygen has killed everyone on the island... maybe even the world!

Written by Robert Towne, best known for Chinatown, Shampoo, and The Last Detail.