Adolescence Medley (4 Episodes)

Kwak Dong Yun as Choi Jeung Woo
Lee Se Young as Yang Ah Yeong

History of a Salaryman (24 Episodes)

Jung Ryu Won as Baek Yeo Chi
Lee Bum Soo as Oh Yoo Bang
Jung Gyu Woon as Choi Hang Woo
Hong Soo Hyun as Cha Woo Hee

 http://wiki.d-addicts.com/History_of_the_Salaryman
One night Yoo Bang (Lee Bum Soo) enters a dark, mysterious villa with nothing but a flashlight, only to find an executive of the Chunha Medical Group, Ho Hae slouched in a chair, dead and Jin Ho Hae's niece, Yeo Chi (Jung Ryu Won) hiding behind a curtain. At Ho Hae's funeral, Yoo Bang and Yeo Chi are suddenly taken into custody for his murder. We're taken three months into the past to reveal what led to this murder and exactly who was responsible.