A cruise on the Pacific goes all wrong, the ship sinks, and there are only 3 Survivors; Joe, Sam and Susie.
They manage to swim to a small island and they live there for a couple of years doing what's natural for men and women to do.
After several years of casual sex, all the time, Susie felt absolutely horrible about what she was doing.
She felt having sex with both Joe and Sam was so immoral and bad that she killed herself..
It was tragic, but Joe and Sam managed to get through it. After a while, Joe and Sam's resistance to nature's urgings waned, and the inevitable happened.
Well, a couple more years went by and Joe and Sam began to feel absolutely horrible about what they were doing.
ISo, they buried Susie.