Best Interests is the story of a family driven apart by having to make choices no parent would ever want to make. Andrew and Nicci's daughter, Marnie, has a life-threatening condition. The doctors believe it is in her best interests to be allowed to die, but her loving family disagree. They start a fight that will take them through every stage of a legal process, as they struggle to contemplate this huge decision. Who decides? And in whose best interests will it be?