Obsession tells the story of an obsessive man trying to win the heart of the woman he loves. Mert, a successful businessman who is loved by his surroundings, is an obsessive person. Finding himself in difficult situations due to his obsession with order, Mert falls in love with a young woman named Beren. Mert makes various plans to win Beren's heart. However, Beren has hidden secrets that no one can guess.