In LONGITUDE, an 18th-century clock maker named Jon Harrison (Michael Gambon) begins what is to become a 40-year task to invent a system for determining longitude at sea with a nautical timepiece. Meanwhile, 200 years in the future, naval officer Rupert Gould (Jeremy Irons) discovers Harrison's neglected chronometers and sets out to restore them. LONGITUDE is a high seas saga of passion, determination, and discovery.