In the hollow at the foot of the tree lived a poisonous black snake. He used to climb up and eat the crane's youngs after they were hatched.
One crane, who had lost her children to the cunning black snake, started weeping on the banks of the lake.
The crane replied, "I am the unlucky mother, all of whose children have been eaten by the wicked black snake, who lives in the hollow of the tree. What else can I do but weep? I would have killed the snake if I could!"
The crab thought for a while, "I have to devise a plan to have the black snake killed, and have the cranes destroyed at the same time. The cranes are our natural enemy. I will tell him half truth and half lies, to my advantage."
Thinking so, the crab said to the crane, "Aunty! I will tell you a plan to get rid of the black snake. All you have to do is scatter some fish and flesh from a nearby burrow, where a mongoose lives, to the snake's hollow. When the mongoose will come following the food and reach the snake's home, he will certainly kill him!"
The crane agreed to do as the crab planned. As anticipated, the mongoose saw the black snake while following the trail of food. They had a fight, and the mongoose killed the snake.
After this, the mongoose realized that there were many cranes on the top of the trees. In due course of time, the mongoose climbed up the trees and started killing the cranes, till all the cranes were destroyed.