The married police officer Hae-jun (Park Hae-il) meets the young widow Seo-rae (Tang Wei), whose husband died in an accident. Although Hae-jun leads a full and good life, he begins to obsessively spend nights in front of the mysterious woman's house. He watches with tenderness as she lonely eats ice cream from a box instead of preparing dinner. The detective's investigations bring him ever closer to this femme fatale, catapulting them both into a spiral of lustful addiction.