Martin Clunes follows humans' relationship with horses through the ages, exploring the animal's role in warfare, ceremony, farming, transport, sport and leisure. Martin begins on his farm in Dorset, where he introduces his equine family, before travelling to Dubai for the grand opening of the Meydan Racecourse and to hear from jockey Frankie Dettori and trainer Luca Cumani. He also visits Mongolia and the South of France, and meets horse whisperer Monty Roberts.

Martin Clunes concludes his worldwide search to discover the secrets of man's partnership with horses. In Italy, he watches the colourful Palio horse race, which dates back to the 13th century. Then, he rides into battle in a suit of armour at Warwick Castle before witnessing the pomp and ceremony as horses and carriages are prepared for the State Opening of Parliament. On a visit to the USA, he sees how rodeo horses are treated like kings in Las Vegas. Finally, he travels to the remotest parts of central Asia to meet some of the world's greatest horsepeople.