Travis Macy and his father Mark "Mace" Macy are two icons in the world of endurance racing. But in 2018, they were suddenly faced with they biggest challenge ever when Mace was diagnosed with early onset Alzheimer's. Everyone, including Mace's doctor, said their days of competing in the world's toughest and longest races were over. Everyone, except Travis and Mace, who not only kept going but wrote a book about it.