Once upon a time when the Jade Emperor decided to choose 12 animals to help him rule every years. He made a race where all animals would chase from the Bottom land to the Gate of Zenith. Here're the competitors - Water Buffalo, Tiger, Dragon, Snake, Horse, Goat, Monkey, Rooster, Dog, Pig. 

And especially, a Cat and a Mouse.

The Cat was an arrogance and lazy itself. He made the Mouse as his servant and command him to alert when the time had come to race, and then he took a long long nap. Unfortunately, the Mouse was sly and tricky, he ran off without calling the Cat awake.

Therefore, until the Cat was finally up, he was late.

The Cat went on a rage! He was so so ANGRY!!! He chase after the Mouse and overcame so many animals, but he're still faraway from the first. The Mouse in the other hand, got on the Buffalo and chilling while the poor creature carried them all to finish line. 

When the Gate finally appeared, the Mouse suddenly jumped out and took the First place so the poor Buffalo only came in 2nd. 

The Cat at last came at the Fourth place.

After losing the Mouse, the Cat was so angry and full of hatreds that he swore to kill all the mice. 

Since that day, cat and mouse become enemies for forever and ever...