The coastal adventure kicks off along three very different, dramatic coastlines, as Helen, JB and Jules explore glorious landscapes, underground wonders and meet the fascinating people who know all the secrets.

In North Yorkshire, Helen descends 4,500 feet into the UK's deepest mine - an extraordinary undersea world and the only place on Earth where Polyhalite is extracted. She gets a real taste of mining life: a creaky lift ride, 35-degree heat, and the rumble of a multi-tonne mining machine. Back on the surface, she swaps drills for thrills, meeting a Redcar land sailing legend and joining the wind-powered action on the beach. There's even time for a Teesside classic - the Parmo. Chicken, béchamel and cheese? Yes please!

Down on the Kent coast, JB explores the strange beauty of Dungeness - a vast shingle headland and a haven for unlikely wildlife. From laughing frogs to leeches he discovers just how wild Britain's only desert can get. At Broadstairs beach, he meets heroic rescue dogs whose super-snouts are saving lives along the shore.
Meanwhile, Jules is in Devon, setting sail from Salcombe aboard the iconic Yawl - the pride of the south coast. Then it's into the depths of Beer Quarry Caves, a sprawling labyrinth hand-carved over 2,000 years. Among the Roman coins and medieval carvings, he stumbles across something unexpected: a local male voice choir, drawn here not just for the history, but for the incredible acoustics – the best in the country!

And while they may be hundreds of miles apart, the banter's never far away as Helen, JB and Jules share all their adventures with each other.

The coastal adventure continues as Helen, Jules and JB explore the wild shorelines of Cumbria, Aberdeenshire and Suffolk, uncovering stories of smuggling, seafaring and surprising seafood.

In South-West Scotland, Helen heads off-road into the rolling hills of Bainloch Deer Park, home to over 600 Red, Sika and Fallow Deer. Alongside park manager Richard, she sets out in a 4x4 to get up close to the herd and discover how this enclosed sanctuary offers a vital refuge from modern threats. Then it's time to take to the water - Helen grabs a paddle and joins the Kirkcudbright Kayak Club to uncover the region's colourful history of 18th-century smuggling. With taxes sky-high on goods like tea and tobacco, cunning traders turned to the Isle of Man for cheaper contraband and launched secret coastal trades that helped fuel the local economy.

Further north, Jules explores the dark history of HMP Peterhead - Scotland's own Alcatraz. Built by convicts using locally quarried granite, the prison housed some of the country's toughest criminals. Now a museum, Jules explores its past with a present-day officer. Then, in Johnshaven, he finds a tastier tale: lobster, once a "poor man's food", is making a local comeback thanks to a community-led lobster shop and café reconnecting residents with their seafood roots.

On the Suffolk coast, JB gets hands-on with a spectacular reconstruction of the Sutton Hoo ship. He joins a team of volunteers' hand-building a full-size replica of the legendary Anglo-Saxon burial vessel using ancient tools and techniques. Finally, he fast-forwards to the present with a crash course in wing foiling at Felixstowe. Balancing on a hydrofoil while harnessing the wind, JB attempts to fly above the water's surface - gracefully or not!

And as always, the team share updates, banter and a bit of coastal competition from three very different corners of the UK.