Last Woman on Earth (1960)
Ev, along with her husband, Harold, and their lawyer friend Martin, are scuba diving while on vacation in Puerto Rico. When they resurface, they gradually conclude that an unexplained, temporary interruption of oxygen has killed everyone on the island... maybe even the world!
- A rich man Harold Gern (Antony Carbone), busy with making money and spending it just as fast, is newly married with Evelyn (Betsy Jones-Moreland) and on his honeymoon in Puerto Rico. His lawyer Martin Joyce (Robert Towne as Edward Wain) is there too on business to try and get him out of a situation with the government. Harold gambles a lot and one day decides to deal with the lawyer by going fishing and scuba diving. Evelyn keeps flirting with Martin, the lawyer. Clearly, she is bored, and annoyed with the life she has married into.
The three go underwater fishing and after a small accident with a spear gun, they all come up to the boat. When they remove their air apparatus, they can't breath. Keeping the air tanks, they go back to shore to find help. As they cross the jungle to get to town quicker, they run out of air, but they realize plants give out oxygen and they are able to breath once again. They discover that everyone, even animals, are all dead.
To avoid the stink and disease, they move to a villa on the corner of the island and begin to make the best of things there. They plan to eventually move to a colder place like northern Canada to avoid pests like ants, that managed to survive.
There is only one women and they are two men. Tension and the need for a woman begin to effect the two men and eventually they get into a fight. Harold hits Martin on the head first with a rock and later with the butt of a gun. The concussion is more than Martin can take and he eventually dies. Harold and Eve are the only ones left in the world.