morale

A fly is flying above a river.

A fish swims in the river and thinks ' if the fly flies lower, I could jump out of the river and catch the fly.'

Next to the river is a bear, he thinks 'if the fly flies lower and the fish catches the fly, I can catch the fish and eat it.'

In the bushes near the river is a hunter, eating a sandwich. He thinks 'if the fly flies lower and the fish catches the fly, the bear will catch the fish and I can get close enough to the bear to shoot it.'

Behind the bushes is a tree with a hole in the ground. There is a mouse in front of it. He thinks ' if the fly flies lower and the fish catches the fly, the bear will catch the fish and eat it. The hunter will get close enough to shoot the bear and the breadcrumbs will fall on the ground and I can eat the breadcrumbs.'

In the tree is a cat. She sees all that is happening and thinks ' if the fly flies lower and the fish catches the fly, the bear will catch the fish and the hunter can get close enough to shoot the bear and the breadcrumbs will fall, so the mouse will go away from his hole and eat the breadcrumbs. Then I can eat the mouse.'

So it happens.
The fly flies lower.
The fish catches the fly.
The bear catches and eats the fish.
The hunter gets close enough to shoot the bear.
The breadcrumbs fall on the ground.
The mouse runs to the breadcrumbs and starts eating.
The cat doesn't think twice and gets out of the tree and runs towards the mouse. She takes a huge leap to the mouse.
The mouse noticed the cat and jumps to the side.
The cat misses the mouse and she falls into the river.

What is the morale of this story?