A Wolf was eating delicious food and a bone got stuck in his throat.
He couldn't get it up or down. He also couldn't eat anything.
He was in an awful state.
He found a Crane and hurried toward her.
He was sure with her long neck and beak, she will be able to reach the bone and pull it out.
The Wolf said, "If you can help me, I will reward you greatly."
The Crane of course was worried she will be eaten by the Wolf and hesitated to help.
But she was nice in nature, so she pulled out the bone for the Wolf.
When the Wolf saw the bone was gone, he started to walk away.
"What about my reward!?" asked the Crane
"Your reward is already given to you. I didn't eat you when I had a chance!"
Lesson: Expect no reward for serving the evil