The show features five members from four disbanded or inactive "first-generation" K-pop idol groups, which debuted during the 1990s: H.O.T. (1996–2001), Sechs Kies (1997–2000; 2016–Present), NRG (1997–2006; 2017–Present) and g.o.d (1999–Present). Moon Hee Joon, leader of H.O.T., personally invited his H.O.T. bandmate Tony An, Sechs Kies leader and rapper Eun Ji Won, dancer and singer-songwriter Chun Myung-hoon of NRG and rapper Danny Ahn of g.o.d, all of whom were born in the same year (1978) and have remained active in the entertainment industry. They would meet in a rented house where they could have a candid chat about issues and topics that they had not been able to speak about due to the closed and highly taciturn culture of the K-pop industry while they were active as members of their groups. Moon had proposed the concept of the show following the success of the television series Reply 1997 and a renewed interest in first-generation K-pop idol groups. (Source: Wikipedia)