It is believed that there is a story behind this festival. Once there was a king named hiranyakashiyap, who got a boon that he will never die. So he started thinking that god is nothing in front of him and he thought that he is himself a god. He started punishing all the devotees of god. But his son Prahlad was against him and he was a devotee of god vishnu.
Hiranyakashiyap tried to kill him many times but he failed. One day he asked his sister, holika to kill prahlad. As holika had a shawl which kept her away from burning, she tricked him and made him to sit in between fire. As fire burnt her shawl flew away and holika burnt. Later god vishnu appeared in the form of narasimha to kill hiranyakashiyap.