Miniseries based on Dava Sobel's nonfiction book about scientists in the 18th century who tried to invent the concept of longitude, and clockmaker John Harrison, who eventually succeeded. The story cuts between the 18th century, when it explores Harrison's life and work, and the 20th century, when naval officer Rupert Gould discovers Harrison's abandoned clocks and works on restoring them.
Countless sea voyages ended in catastrophe because of an inability to mark an exact position in the world's oceans. A need to accurately measure longitude at sea became a priority. In 1714, the British Parliament offered a huge reward to anyone who could find the answer. While most looked to the stars for navigational guidance, one person, John Harrison, dared to imagine a mechanical solution in the form of a clock. The world thought his idea preposterous, but Harrison continued to dream and his vision forever influenced the way mankind would view time and travel.
In 20th century England, 150 years later, a shell-shocked naval officer, Rupert Gould, rediscovers four "clocks" built by Harrison and begins the mammoth task of restoring them, and their reputation, to their majestic glory. It is due to Gould's commitment to this cause -- at the expense of his health, marriage and career -- that Harrison's clocks finally received the recognition they truly deserved.