In April 2013, a lecturer at the University of New Hampshire submitted a paper to the Annals of Mathematics. Within weeks word spread— a little-known mathematician, with no permanent job, working in complete isolation had made an important breakthrough towards solving the Twin Prime Conjecture. Yitang Zhang’s techniques for bounding the gaps between primes soon led to rapid progress by the Polymath Group, and a further innovation by James Maynard. The film is a study of Zhang’s rise from obscurity and a disadvantaged youth to mathematical celebrity. The story of quiet perseverance amidst adversity, and Zhang’s preference for thinking and working in solitude, is interwoven with a history of the Twin Prime Conjecture as told by several mathematicians, many of whom have wrestled with this enormously challenging problem in Number Theory— Daniel Goldston, Kannan Soundararajan, Andrew Granville, Peter Sarnak, Enrico Bombieri, James Maynard, Nicholas Katz, David Eisenbud, Ken Ribet, and Terry Tao.