In November 1938 Jewish shops and businesses are brutally attacked in several days of pogroms in what became known as Kristillnacht. Charles’ position of trying to build good relations with the Nazi leadership now becomes untenable. He has a bruising showdown with his cousin, Winston Churchill, at a social event in London. In private, he acknowledges that he has failed in his efforts to be an architect of peace like his illustrious ancestor, Lord Castlereagh. World War Two begins in September 1939 and Charles and Edith go back to Mount Stewart in County Down. But it follows them to the shores of Strangford Lough as German bombers target Newtownards Airfield in 1941, killing 13 air cadets - mainly young men. Charles attends the funeral of one of them, realising that the war he struggled to avoid is now a reality. He uses his skills as a pilot to help train young men in flying but in 1945 he is involved in a near-fatal glider accident. The war ends in victory - but Charles’ health is in decline. He is asked to give written evidence by the defence team for Joachim von Ribbentrop at the Nuremberg trials. The Nazi Minister for Foreign Affairs claims he always tried to steer Hitler towards a more limited war. Ten years on from the Ribbentrop’s visit to Mount Stewart, Charles gives scrupulously accurate evidence which does not corroborate the Nazi’s claims of being a peace-maker. A death sentence is passed and Ribbentrop dies by a lengthy hanging. Charles himself dies three years later, aged 70 and is buried at Mount Stewart in the family plot, Tír Na nÓg - ‘the land of youth’. Striking up personal relationships with Nazi leadership had come to define his legacy. It had caused huge turmoil in his life but now, finally, he is at peace.

Prominent Nazi, Joachim von Ribbentrop, visits the Londonderrys again – this time at their stately home in the North East of England. But the German ambassador is on the point of giving a Nazi salute in Durham Cathedral and just in time Charles, Lord Londonderry, grabs his arm to avoid an embarrassing scandal. Charles’ friendly relations with senior Nazis are threatening to destroy his public reputation and he was is not the only one. The Nazis prove to be a source of huge fascination for the Anglo-Irish aristocracy at this time - some are drawn to them while others are repelled. Either way, they cannot be ignored. This is true particularly of Charles Londonderry as he made makes a total of six trips between 1936 and 1938 to meet them. Yet his awareness of the threat that a strong, militarised Germany poses is acute. The Anschluss uniting Germany and Austria became becomes one more example of this and German moves that constantly pull the rug from under Charles’ one-man diplomatic strategy. Charles had previously lost his job as Air Minister in Westminster in 1935 when it emerged that he had seriously underestimated German military air strength. Charles was distraught and disputed that any fault lay with him until till the end of his life. His sacking wounded him deeply and consequntly he forms a plan with Edith to forge links with the Nazis to bring them into the European family of nations – following in the footsteps of Lord Castlereagh. Charles believes in diplomacy and negotiation – but injured pride also plays a huge part in his actions as the clouds of war gather. When British PM Joseph Chamberlain flies to Munich to meet Hitler and sign a peace agreement in 1938, Charles believes he has finally been vindicated. But only a few weeks later, Germany invades its neighbour Czechoslovakia. The world waits for war.

Spring 1936. A man falls into Strangford Lough and has to be fished out. It is a huge humiliation for Hitler’s leading diplomat, Joachim von Ribbentrop. But some say this story is just a myth. Claims and counter-claims swirl around Charles, Marquess of Londonderry and his wife Edith because of their friendly relations with high-ranking Nazis. The mystery of whether Ribbentrop fell into the water on a weekend trip to Mount Stewart house in Co Down typifies how accounts of the Londonderrys can diverge wildly. Earlier in 1936, the Londonderrys had visited Berlin to meet Hitler and Herman Goring at lavish social events. Incredibly, they have brought their 14 year old daughter, Lady Mairi, who ends up chatting with Hitler about a comedy film they have both seen. After the trip there are adoring letters sent to thank the Nazis for their lavish hospitality. But clouds are gathering. Just days after their return, German troops march into the Rhineland – a move strictly forbidden by the Versailles treaty that concluded WW1. Is Europe on the brink of another war? Charles believes Germany in in the right and he and Edith make more visits to Germany. But when they invite Ribbentrop to Mount Stewart it is for many a step too far and the criticism in Westminster and in public opinion is intense. However, Charles thinks that Germany can be reigned in – IF they can be brought to the international negotiating table. He is inspired by his famous ancestor, Lord Castlereagh who redrew the map of Europe to bring a century of peace after the Napoleonic Wars. But no one in government wants to listen to him and his own antisemitism begs the question of whether he has more in common with the Nazis than he thinks.