In the woods there was three brown mice, and one white mouse.
Every night the lion comes into the woods to try and find its prey. Its favorite food is a mouse.
All of the mice get very scared at night, because they know the lion wants to eat them
The lion came into the woods looking for a tasty treat. He immediately noticed the white mouse who did not blend in with the environment. He did not notice the brown mice that blended in with the trees.
The lion spotted the little tasty mouse, and he ate him.
The brown mice lived another day because their brown color let them blend into their surrounding, they went on to pass their brown color onto many other mice.