Season 0 of While You Were Sleeping premiered on 2017-09-24.

Nam Hong Ju, endowed with the ability to foresee events, resides with her widowed mother who runs a small restaurant. Despite her gift, she often finds herself powerless to change the outcomes. On the other side of the street, Jung Jae Chan, a rookie prosecutor, and his younger brother Seung Won become their new neighbors. An unusual dream involving Hong Ju, ruthless attorney Lee Yu Beom, and a life-saving intervention leads Jae Chan to realize their destinies are intertwined, as they begin sharing dreams and connecting in mysterious ways.