In one of the most intense experiences of his life, Grimsby-based Guy Martin takes on the dangerous job of working as a deckhand on a fishing trawler.

The Calf of Man is a remote island in the Irish Sea, just off the coast of the Isle of Man. It is a nature reserve, with just four permanent residents who live off-grid, monitoring wildlife and maintaining the wild habitats. Guy joins these wardens in their conservation work, trying his hand at birdwatching, rat catching and cleaning up a beach that's a favourite with pregnant seals.

Guy Martin follows in the footsteps of his brother and sister, both of whom were firefighters - "well, I suppose it's in the blood". Before dawn, Guy arrives at Peak's Lane Fire Station in Grimsby – the town's busiest station – to work a full 24-hour shift on Green Watch. As well as joining the crew of Papa 4 on any call outs through the day - "got to drive through Grimsby with the dee-daas going!", Guy mucks in with cooking meals, works out in a gym for the first time in his life and learns why his fellow firefighters joined the service, what motivates them and how they cope with the harder parts of the job.

Guy heads to the Cairngorms – one of Britain's most dangerous mountain ranges – where he's given an intense course of Mountain Rescue training and learns a little about why the volunteers who do this extreme job repeatedly risk everything to save others. Then he practices, repeatedly, how to work with an experienced search and rescue dog called Pippa, learning how to efficiently cover a search area with her.