Fi is a first internet TV series in Turkey, the Turkish psychological thriller television series originally streamed online by puhutv. It is an adaptation of award-winning author Azra Kohen's trilogy novels Fi, Çi, and Pi. Its first season consists of 12 episodes which were released from 31 March 2017 to 16 June 2017. The second season started in October 2017. Within 50 hours of the first three episodes being released, it reached 3.5 million viewers.