Bill Andrews and Aubrey de Grey both believe aging is a disease, not an inevitability, and this film follows their separate attempts to cure it. Andrews, a molecular biologist, works on telomeres, the protective caps on chromosome ends that shorten as cells divide, and has developed a compound called TAM-818 meant to stop that shortening. De Grey, a biomedical gerontologist, pursues a different strategy called Strategies for Engineered Negligible Senescence, aimed at identifying and reversing seven categories of cellular damage that accumulate with age. The camera follows both men in their labs and in their daily lives, including Andrews, in his sixties, pushing himself through endurance training to prove his own theories in his own body, and de Grey's more indifferent attitude toward his personal health despite his research goals. Neither man has proof his approach works, and the film does not pretend otherwise, letting their competing methods and personalities carry the argument about whether aging can be treated like any other disease rather than accepted as fate.