She and some regular guy are the only two survivors. They make the best of their situation, scavenge what supplies they can from the plane, and try to keep going.
They build a little hut on the beach and – both of them having certain “needs” – eventually start hooking up.
This keep going as months turn into years and they fall in love. One day she notices he looks depressed. Scarlett says to him, “Listen, that plane crash was the best thing that ever happened to me because it means that the two of us are together. If there is anything at all I can do to cheer you up, please let me know.”
He tells her, “Actually, there is something. Put on a set of my clothes and tuck your hair up under one of my hats. Rub mud on your face so it looks like a beard and start walking down the beach.” Scarlett thinks this is weird but, wanting to make him happy, goes along with it. Once she gets about 200 yards down she turns around and sees her boyfriend running up to her shouting, “BRO! BRO! You’ll never believe who I’m sleeping with!”