Set in Seoul, South Korea, No Regret centers on Sumin (Lee Young-Hoon), who leaves the orphanage where he grew up and heads to the city to study art design. After losing his job at a factory due to layoffs, he finds himself working as a prostitute in a gay bar. Initially Sumin resists the advances of Jaemin (Lee Han), who comes from a rich and conservative family that doesn't accept his sexual identity. Eventually Sumin succumbs to Jaemin's advances, after they briefly experience happiness as passionate lovers, Sumin and Jaemin's relationship falls into heartache and tragedy.