In 1714, England's Parliament offered a large reward to anyone who could discover a way to accurately measure longitude at sea to prevent nautical disasters. Carpenter John Harrison (Gambon) decided on a mechanical solution in the form of a clock (now known as the marine chronometer) and strove to have his ideas excepted (for 40 years). His story is paralleled with that of shellshocked ex-WWI soldier Rupert Gould (Irons), who discovered Harrison's neglected originals and became equally obsessed with restoring them to working order. The performances carry the somewhat diffuse plot. Based on the book by Dava Sobel.