There was a poor fisherman lived nearby the river in North Kalimantan. He went fishing early every morning and always returned to his home at night time. One day, he set up his net and caught a big golden fish. He fell in love with the beauty of the fish that he decided not to kill the fish, and made it as a pet instead. So, he took the fish home, cleaned a fish tank and put it in his humble kitchen.
Starting that day, things changed slowly. Every morning the fisherman went out for fishing, no matter how he left his home in a mess, when he returned home, the house would be tidy again. Furthermore, there was always delicious food served on his dining table. The fisherman never knew how it happened, and where the food came from, and who prepared them for him. It brought enormous curiosity to him that he decided to search for the truth.
That morning, he went out as usual, but right when he set out his feet outside, quickly and quietly, he made a turn back to his house. Hiding behind his own window, he took a peep of what happen in the house soon after he left it. Suddenly from inside the kitchen, he could see a bright light shining, and soon after the light disappeared, he could see the fish tank was empty, and a beautiful lady was standing inside his kitchen. The lady quickly got some vegetables and did some cooking. She even cleaned the whole house, sweeping and washing the fisherman's clothes. The fisherman fell in love at the first sight. Before the lady could runaway, the fisherman grabbed her hand and proposed to marry her.
At first, the lady refused for she was just a fish rescued by him. Her deed was a grateful act to repay the fisherman's kindness for not killing her. But since the fisherman time and again persuaded her to marry him, the lady could not refuse him. She agreed to become the fisherman's wife with one condition, that the fisherman promised not to tell anyone - not even his own family - that she was just a fish. The fisherman promised her.
Years went by, the fisherman lived happily with his wife, and changed his work and became a farmer. His wife soon became pregnant and delivered a baby girl that they named "Samosir". Samosir grew up into a pretty girl and obedient as well. She loved to help her parents working in the house or in the farm. One morning, her mother asked her to send lunch to her father in the farm. Samosir was glad to help her mother that she immediately got the basket and headed to the farm.
It was such a long way to got to the farm, that Samosir who had not had any breakfast before, grew tired and hungry. So she stopped to eat a little food from her father's lunch to ease her hunger. Afterward, she continued her journey, however, she became hungry again and had to eat a little food again. This happened again and again till finally her father's lunch was finished. When Samosir gave the basket to her father, how angry her father was to get an empty basket.
"I'm tired working the whole day and expect you to bring some food from your mother, but you finish them all without even thinking of me. How could you? You! A daughter of a fish!" shouted her father in anger.
Samosir ran home crying and telling her mother what had happened. She even asked her mother why her father told her that she was a daughter of a fish. When the mother knew that her husband had eventually broken his promise, she was terribly sad. In tears, she packed all her daughter's clothes and asked her to runaway to the mountain, never look back, and stay there. Samosir did not understand, but she promised to obey her mother.
When the mother was sure that her daughter was safe, she whispered something and slowly she turned herself into a giant fish. The water from river was flooding her house and it came more and more and more that the whole village was flooded and finally disappeared from the earth.
From the top of the mountain, Samosir could only cry to see her village was drowned and the flood surrounded her hiding place. Since then, the place turned into a lake and we called it Lake Toba, and the island in the middle was named after the girl's name, 'Samosir Island'. We can still visit the lake now, and one of the most beautiful lakes in Sumatra island, Indonesia.