Once upon a time, there was a fisherman lived in a North Sumatera. One day when he was fishing in a river the fisherman caught a fish. He was surprised to find the fish could talk. It begged him to let it free. As soon as the fish was free, it changed into a beautiful woman. The fisherman asked her to marry him. She agreed. However, she told him that he should never let out the secret that she was once a fish. He promised her that he would not tell anyone about it. They lived happily and had two daughters.
One day when the man went out fishing, his daughters brought him his lunch. However, instead of bringing the food to their father, the two girls ate it. When their father knew it he got very angry. He shouted, “ You behaved exactly like the daughters of a fish.” They went home and told their mother about it. Their mother was very annoyed. She would not forgive him for breaking the promise.
Then the earth began to shake, and volcanoes started to erupt. The earth cracked and formed a big hole. People said that the hole became Lake Toba.