Two people are lost in the desert. They are dying from hunger and thirst. Finally, they come to a high wall. On the other side they can hear the sound of a waterfall and birds singing. Above, they can see the branches of a lush tree extending over the top of the wall. Its fruit look delicious.
One of them manages to climb over the wall and disappears down the other side. The other, instead, returns to the desert to help other lost travelers find their way to the oasis.