A story of three brothers and their one sister who share a bond so strong it feels like a fifth element. In a world that often tries to pull them in different directions, they are each other's home and safe harbor. From the triumphs of their careers to the quiet heartbreaks of their personal lives, they are an unbreakable quartet, a support system built on laughter, loyalty, and an almost psychic understanding of one another. When a secret from their family’s past resurfaces, threatening to fracture their solid foundation, they must confront their deepest fears and re-learn what it means to be a family—and to be four.