"Bırak Zaman Aksın" ("Let Time Flow"), their second album was released in January 1999 and met with success. Just after its release, Derin Esmer moved to the United States and was replaced by prominent guitarist Kerem Özyeğen. After the devastating 1999 Kocaeli earthquake, Mor ve Ötesi started exploring more social and political themes. They were also very active in the opposition against the use of nuclear energy in Turkey.