Set in the late 1970s, somewhere in the Mediterranean, “The Birthday Party” tells the story of Marcos Timoleón, a tycoon in the style of Aristóteles Onassis, who organizes a lavish birthday party for Sofía, his daughter and only heir, on his exclusive private island. The party serves as the perfect excuse for various people from Marcos’ life to approach him with their own agendas. However, Marcos, used to controlling everything and everyone around him without hesitation, is secretly planning a major decision concerning his daughter. Sofía, for her part, also has important news to share. As the guests arrive and night falls, the party becomes increasingly wild and decadent, while the inevitable clash between Marcos and Sofía reaches a heartbreaking climax.