The film revolves around the life of Srinivasa Ramanujan (played by Devika Bose), a young and self-taught mathematician from India who, in 1913, sent a letter to Cambridge University professor G.H. Hardy (played by Jeremy Irons), showcasing his groundbreaking mathematical discoveries. Impressed by Ramanujan's work, Hardy travels to India to find him and invites him to Cambridge University to collaborate on his research. The movie follows their remarkable partnership and the significant contributions they made to mathematics, particularly in the fields of number theory, elliptic curves, and infinite series.