Kaal Bhairav Rahasya (transl. The mystery of Kaal Bhairav) is an Indian thriller television series. The series ran for two seasons from October 2017 to April 2019. Both seasons are based on written works of Indra Soundarrajan. The story of first season is based on his Tamil novel A Secret (Ragasiyamaga Oru Ragasiyam), The second season story is based on the supernatural thriller tale of Soundarrajan titled The Palace of Kottaipuram (Kottai Purathu Veedu). The series featured different cast in each season although many cast members appeared in both seasons as different characters