 The Enterprise, carrying a critically ill Federation Ambassador Nancy Hedford, encounter a mysterious energy cloud which pulls them down to planet Gamma Canaris N, where they meet a castaway. This young man purports to be Zefram Cochrane, the inventor of the Warp Drive over 100 years ago. But in history he had lived to be 80 years of age before disappearing somewhere in space. Apparently the same energy cloud which brought the Enterprise to the planet also rejuvenated Cochrane, making him effectively immortal. Can Kirk get the Enterprise released on time to get the ambassador the medical help she needs, or is there something else in this situation which might be a solution?