A once-in-a-lifetime journey aboard the most famous train in history, the Flying Scotsman, begins for Michael Portillo before dawn at London's King's Cross station. Excitement builds as the world's media, railway fans and 300 passengers await the arrival of railway royalty. Boarding a vintage carriage, Michael recaptures the glamour of the 1930s. But his journey soon comes to a grinding halt.

Michael begins a new journey north from London, but he’s forced to expend more effort than usual as he pumps a track inspection trolley, then gets the chance to drive a 'locomobile'. He then goes back to school at Haileybury, where the master is unimpressed by Portillo's exam performance. Finally, Michael discovers a treasure trove of Victorian plant and soil samples.

Michael starts the latest leg of his journey in the 'Key of the North', Newark-on-Trent. He rallies the choristers of a Tudor song school and admires the art of the railways before travelling to Retford, where he discovers a high-tech application for Victorian rubber technology. A scandalous novel written in Thirsk leads Michael to a wildlife center, where he feeds a hungry young hedgehog.

Michael steps back in time as he follows the route taken by George Stephenson's steam engine on its historic journey in 1825. Through the looking glass at Croft-on-Tees, he discovers a curious potion at the childhood home of Victorian writer Charles Dodgson, better known as Alice in Wonderland author Lewis Carroll. And in the coastal village of Craster, Michael learns how to smoke a kipper.

Michael Portillo concludes his journey from London to Edinburgh. He helps himself to a ukulele lesson in Haddington, in Musselburgh he gets a taste of life as a fishwife before exploring the Scottish capital Edinburgh, where a 19th-century mode of transport is making a comeback. He then discovers the macabre history of body snatchers and murderers who contributed to the science of anatomy.

Michael Portillo embarks on a new journey across Bradshaw's Britain with his Victorian guidebook, starting in Blackpool. He heads towards Manchester, where George Stephenson built the world's first modern railway line. At a moving ceremony in Manchester Piccadilly station, Michael unveils a new monument to workers of the London and North Western Railway, who lost their lives in the Great War.

Michael Portillo's journey from the Irish Sea to the North Sea continues by tram from Manchester. At the imposing town hall, Michael comes face to face with the Victorian scientist who invented modern atomic theory. At Silkstone Common, he tracks down the forge where wrought iron axles for trains were created and is delighted to discover the factory contains a miniature wonder.

Michael heads to Wharncliffe Crags, where he follows in the terrifying footholds of the Victorian daredevil who made rock climbing a sport. The relative calm of academia beckons at Sheffield University but, face to face with a hagfish, his visit to the Alfred Denny Collection proves an eye-opener. Then Michael visits the castle which inspired Sir Walter Scott's immensely popular novel, Ivanhoe.

Steered by his Bradshaw's railway handbook to Gainsborough, Michael Portillo wraps his head around an ingenious Victorian machine which changed shopping forever. In Lincoln, he discovers the verse and popularity of 19th-century poet laureate Alfred, Lord Tennyson, and finds poetry thrives today in a city pub. At Ely, Michael discovers the architecture of the city's magnificent cathedral.

Michael Portillo is on the final leg of his journey, heading to Harwich. Along the way he meets volunteers on the Mid-Suffolk Light railway and is allowed to drive ‘The Middy’. In Leiston, he uncovers the world’s first purpose-built assembly line. The work of a young Victorian engineering prodigy impresses Michael in Ipswich. In Harwich, he discovers how the port became a gateway to the continent.

Michael Portillo begins his journey across Ireland in the port of Wexford, where he takes to the seas in a 100-year-old lifeboat and discovers a hero of the American Navy. In Wicklow, he learns of a Victorian project to combat disease in the capital, Dublin. Embracing the gentler pace of life of a Victorian Irish traveler, he ends this leg in a beautiful horse-drawn, barrel-top caravan.

At Trinity College Dublin, Michael discovers one of Ireland’s greatest treasures and learns how it became the symbol of the nation. There’s a chance to sample the black stuff in a Dublin pub before he learns how Victorian royals were deployed to calm rocky relations between Britain and Ireland. Finding an angle on triangulation helps Michael to understand how, and why, Ireland was put on the map.

As his railway journey through Ireland continues, Michael Portillo gets up to speed with modern archaeology in County Meath and uncovers a controversial Victorian dig at the sacred Hill of Tara. He investigates leaping salmon in Leixslip and discovers an electrifying breakthrough at an historic seminary. At Mullingar, Michael bangs the drum for the town’s marching band.

Michael Portillo continues his journey across the Emerald Isle uncovering Irish identity, forged at a time of political strife. He learns how the landscape inspired one of the 20th century’s greatest poets, WB Yeats. In Dromod, he learns how to make an Irish staple, a potato pancake known as Boxty. At the home of the father of Irish fiddling, Michael attempts to master a traditional dance.

On the last leg of Michael Portillo’s long journey from Wexford to Westport, a fashionable Victorian seaweed bath is followed by a steamy scene in Ballina. On tenterhooks in Foxford, Michael discovers the visionary charity of an entrepreneurial nun. He learns of a double tragedy at Clew Bay and begins a pilgrimage to the summit of Ireland’s holy mountain, Croagh Patrick.