Kyungsoo and Jaehoon are brothers from a family of long history where time travellers exist. Following their Father's path they enter the world of time travelling from a young age. It was until when Kyungsoo the youngest of the two is interwined in an accident that changes his life forever. In order keep the world in peace there is one rule any time traveller must keep. Never save or kill a life, and never change someone's destiny or else consequences will always follow.