Once upon a time, a husband and his wife lived in a village. One day, the wife dreamed she was wearing a diamond ring that made her disappear. The wife asked her husband to visit a fortuneteller to interpret the meaning of the dream. The husband relayed the story to the fortune teller, who then predicted that the wife would give birth to a blessed person. The fortuneteller's words were not all positive, however. She issued a grave warning that the wife should not eat green mango or else she would suffer a lethal accident. When the fortuneteller's vision faded, the husband cheerfully returned home, happy that he would soon have a child.

Little time passed before the wife became pregnant. Struck by the same strange cravings most pregnant women endure, the wife developed an insatiable taste for green mango. She asked her husband to climb the mango tree and pick her the biggest fruit he could find. The husband denied her request and instead went to work in the fields. Unable to suppress her urges any longer, the wife climbed the mango tree to claim the prized fruit for herself. Sorrowfully, the rotten branch she stood upon broke, sending the wife hurtling to the ground. She instantly departed from this life.

The wife's stomach burst open and out of it ran a calf and a baby boy who stood still beside his mother's corpse. The calf ran to the fields to inform the father that his newborn son needed help. Hearing the news, the father suffered great regret and sadness that he had lost his wife. Soon realizing that from death comes life, he found joy in his two sons: Preah Keo, the boy, and Preah Ko, the calf.

The villagers could not share the father's happiness. They felt that something strange was approaching their village and quickly decided it was a bad omen. The people gathered together to banish the father, Preak Ko and Preah Keo from the town. The small family refused to admit defeat. With time, the people esteemed the boys for their supremacy and kindheartedness. Preah Ko had the power to heal the village people's sickness, fly and transform into any form. To the great delight of his neighbors, Preah Keo shed his boyish looks and grew into a handsome young man.

One day, Preah Keo was walking by a pond when he spotted a beautiful young woman bathing in the water. She was Neang Pou, daughter of the Khmer king. Shortly after their chance meeting, the pair's love became a reality. News of the relationship reached the king, who grew very annoyed. The king disowned his daughter, refusing to acknowledge her existence. Out of love for his brother, Preah Ko magically produced a luxurious palace for Preah Keo and Neang Pou.

At this time, the Khmer king was faced with a great dilemma: The king of Siam had requested a cockfight between the two countries. The king knew he would be defeated since his cocks were not match for the king of Siam. Preah Ko helped the king by transforming himself into a strong and powerful cock. The Khmer cock pecked at the Siamese cock, earning Cambodia a triumphant victory. The Siamese king became very angry and ordered to have a buffalo fight. Preah Ko changed into a buffalo to defeat his Siamese competitor. His anger growing into a rage, the Siamese king wondered why his Khmer competitors always won and organized a fight between a Khmer bull and a Siamese mechanical bull.

Preah Ko had met his match. Realizing he could not win against the machine, he told his brother and Neang Pou to be ready to fly away with him once he was defeated by the Siamese bull. As they were fleeing from danger, Neang Pou fell down and died instantly. The Siamese king knew of Preah Ko and admired his magical powers. Hoping to own the two brothers, the king deployed many soldiers to seize them, but Preah Ko and Preah Keo hid in secret locations around the area of Longvek. The Siamese king ceaselessly stalked the brothers until they grew tired of the chase. The king's greatest victory was the capture of Preah Ko and Preah Keo. Legend has it that the brothers still are held captive by the king of Siam.

Although the story of Preah Ko and Preah Keo may be only a myth, Khmer people have great respect for the enchanting brothers. In some shrines throughout the country, Khmers have placed statues of Preah Ko and Preah Keo, who keep watch over the land they left but never abandoned.