Obsession — a contemporary four-part adaptation of the 1991 novella from late author Josephine Hart — is described as a "thrilling and seductive limited series about erotic obsession and forbidden desire". The story centers around a dangerous love triangle that emerges when the enigmatic Anna Barton embarks on a passionate affair with her fiancé's father, William. While Anna fights to sustain both relationships, William is drawn into an obsessive spiral. But, how long can they keep their secret hidden before someone gets hurt?