Dosa Cinta follows Adylea (played by Rita Nadira), a college girl on a mission to uncover the dark secret that caused her older sister, Kay (played by Ezzaty Abdullah), to commit suicide six years ago. Adylea then meets the owner of a resort in Langkawi, Mediha (played by Tiz Zaqyah), the wife of Erhad - the perfect man in her eyes. Through this meeting, can Adylea avenge Kesumat's death in order to protect her older sister?