JJ Chalmers learns how a warship performs one of its most dangerous and difficult manoeuvres, refueling at sea. He joins a massive 39 thousand-ton tanker, operated by the Royal Fleet Auxiliary, as it conducts the dangerous operation just 40 metres apart from a moving warship out on the high seas. Kate Humble takes on the extreme Submarine Escape, Rescue, Abandonment & Survival course.

JJ Chalmers heads to HMS Raleigh in Cornwall, the home of Royal Navy training, to see how recruits are prepared for the harsh realities of war. Kate Humble is aboard a warship as a brand-new helicopter pilot takes an important step in their career - landing on the deck of a moving warship at sea for the very first time. Also, JJ explores the legacy of HMS Ark Royal, one of the Navy's most iconic aircraft carriers.