Guy visits the USA, where he hopes to win at one of America's oldest races: the Pike's Peak International Hill Climb. In this annual contest, known as The Race to the Clouds, riders compete against the clock on a gruelling mountainside track that finishes over 4000 metres above sea level. To learn the unique skills required in hill climb racing, Guy heads to the birthplace of the sport: Shelsley Walsh hill climb in Worcestershire. Racing up the course in an F1-style car, he realises that sheer horsepower and driving precision are vital. However, in the thin air of Pike's Peak, Guy's body and bike will be desperately short of oxygen, which could seriously affect his performance. As well as trying to add more power to his homemade bike, Guy takes a high-altitude fitness test in a hypoxic chamber. He soon realises how much harder his body will have to work and how the high altitude will affect his brain and cognitive performance; crucial when he has to remember the 150-plus bends in the road and avoid driving over a cliff! After six months' preparation and a two-day road trip across America, Guy's success depends not just on how well he's tuned his bike and body, but on his own abilities as a racer

In the last episode of the new series, Guy Martin attempts to build and race the world's fastest soapbox racer, creating a unique design, with help from expert designers and bobsled racers, and training with the Team GB women's bobsled pair.

Guy gets back on a bike to see how far it's possible to cycle during 24 hours of non-stop pedalling. With the help of bicycle brainiacs Miles Kingsbury and Mike Burrows, the man who designed Chris Boardman's gold medal-winning Lotus bike from the 1992 Barcelona Olympics, he builds a revolutionary tandem and pairs up with his friend, endurance expert Jason Miles, to see how far they can push their bodies at the Extreme Environments Laboratory at the University of Portsmouth. In the build-up to the final record attempt at the historic Goodwood Motor Circuit, Guy also learns about the science of cooking for athletes with the Head of Nutrition at Team Sky, Nigel Mitchell, who instructs Guy to lose five kilos of weight and recommends a new diet regime. Guy also works out the best ways of relieving himself on the move to save vital seconds. As the day approaches for the record attempt, news reaches the team that Hurricane Bertha is approaching.

Guy tries to cross the English channel on a human-powered airship. His transport takes the form of a bicycle held aloft by a helium balloon the size of a bus, with the pedals driving two propellers. He puts the machine to the test in Bedfordshire's historic Cardington Hangars, where some of the world's biggest flying machines were created, and seeks some military advice on surviving crash landings.

Guy Martin attempts to beat the speed record for a human-powered boat, with help from Olympic legends Sir Chris Hoy and Sir Ben Ainslie

Guy is on a mission to do the seemingly impossible: fly using muscle power alone. He wants to build the world's fastest human powered aircraft: a plane without an engine that Guy will cycle into the air. He heads to Southampton University where, on 9 November 1961, Derek Piggot became the first man to fly under his own power. Forty two years later, Guy is ready to break into the history books with another team from the university. They've got seven months to build a plane from scratch and equip Guy with the skill, power and endurance to pilot it. He begins by learning how to fly a glider with stunt pilot Guy Westgate. He also visits a velodrome to measure his cycling power output and embarks on a programme of intense physical training. Finally, Guy is ready to put his plane to the test against the UK's leading engineers in the Icarus Cup, where he sets out to pilot the fastest ever human powered aircraft.