In 1856, things were largely quiet in Europe. After the end of the Napoleonic Wars, a balance of power known as the "Concert of Europe" had taken root, and every nation was eager to maintain the balance. Even the rising might of Prussia wasn't proving to be too great a threat to the established balance. However, some nations saw the renewal of the traditional Auld Alliance as a threat to that balance, particularly the United Kingdom. Many in the UK government saw the alliance as encircling them in the way they had been in times long since gone like the 1500s. Never since the marriage of Mary I and Francis II had Scotland and France been so close together. What's more, with the situation in Ireland continually deteriorating, London had every reason to feel like it was being boxed in, and that the Concert of Europe was falling apart. As such, the United Kingdom soon began to look for an ally of its own on the continent. Privately, however, the two monarchs of the "opposing" countries trusted each other greatly. Mary IV and Victoria were good friends even as their governments snorted and pawed the ground at each other, exchanging letters often and even occasionally meeting in person.
Regardless of how London felt, there wasn't a valid casus belli, and thus had no real reason to invade. Indeed, invading would turn the sympathies of Europe against the UK, being seen as a larger power unjustly invading a lesser power. With the Concert of Europe still holding together, Scotland had the ability to focus on a larger problem that had presented itself. In North America, the UK's dominion of Canada and Scotland's dominion of Nova Scotia were slowly but steadily receiving an influx of illegal immigrants in the form of escaped slaves from the United States. The so-called "Underground Railroad" had two different termini: Toronto in Canada and Halifax in Nova Scotia. While Toronto was far more common, Nova Scotia had nonetheless received about 7,000 slaves escaped from the USA. The United States, largely driven by the urging of the southern states, had issued a formal protest to both the governments of the two colonies stating that they desired the deportation of all escaped slaves back to the United States to face justice under the Fugitive Slave Act. The government of the Province of Canada quickly said no, but the government of the Dominion of Nova Scotia was wavering on the topic.
On the 18th of April 1857, the renown African-American orator Frederick Douglass, an escaped slave and self-made freeman, famously appeared before the Nova Scotian parliament to give a speech against deportation. An excerpt is given here:
"Honorable Gentlemen of the Parliament, the Negro is only a darker version of the White man. He is said to have no culture, arts, or letters of his own, but I posit that this is only because he has never been afforded a chance to prove himself. The White slave owners of the south say that slavery is good for the African man, that he needs hard labor to make himself productive and fulfilled. And yet, millions of my kind, of the kind whose kin stands before you, rot away in bondage, in shackles, in the hovels of the plantations, in the shadow of the manors that their white masters live in, made off the sweat and all-too-often blood of the African man. The Scottish nation stands for liberty and freedom, fought for by men the likes of William Wallace and Robert the Bruce. Should the slave, desirous of this freedom, be punished for taking liberty into his own hands and escaping to freedom? Gentlemen of the Parliament, stand with us! Stand with us in our fight for freedom!"
The speech resounded with the whole of Scotland. Douglass' speech was reprinted and published throughout the Kingdom, and the Scottish public quickly turned against deportation. The speech swayed the necessary votes against deportation, and Nova Scotia joined Canada in refusing to deport the escaped slaves. The United States was outraged, but with unrest growing rapidly in its own borders, they could do nothing about it. The speech also had an unintended effect: it became very popular in Ireland, where many saw a similarity in their own struggle against English oppression. Douglass' speech began to galvanize the Irish public more, seeking their own freedom in the same way the slaves of the United States were. In mid-1857, many of the Irish nationalist groups merged together to form the Irish Royal Army, often just abbreviated as the IRA, which quickly began to fight to create an independent Irish Kingdom.
Something broke in mid 1858. An abolitionist named John Brown had lead a raid on a Federal arsenal in Mount Vernon in Alabama, and had successfully started distributing arms and guns to slaves all across the south. What started as a spark soon grew into an uncontrollable blaze, a full-scale slave rebellion in the United States. Initially, the European nations were neutral on the subject, but with the slaves soon pushing back against the better-trained and better equipped United States Army through sheer force of manpower alone, along with the resulting collapse of the economy of the southern states, they began to take more interest. The United Kingdom, Scotland, and France in particular began to smuggle supplies and weapons into the rebel-controlled areas. By 1861, the rebellion had resulted in many, many people dead and much more land and area damaged or outright destroyed. However, with more and more experience against the United States, and fighting in a new tactic of war often called "guerrilla warfare", the slaves were doing better and better. Finally, whether by tactical strategy or just sheer luck, the final battle of the war came in 1862, when the slave forces managed to rout US General Robert E. Lee at the Battle of Savannah. With this victory, London, Edinburgh, and Paris officially stepped into the war, and stated that the United States had to make peace.
Begrudgingly, and absolutely humiliated, the United States was forced to both abolish slavery and relinquish the states of Georgia, Alabama, Florida, and Mississippi to the former slaves, which was quickly turned into the Republic of New Afrika. At once, this new Republic, which wasted no time in voting in Frederick Douglass as its President, formed an alliance with the three nations that had propped it up. A colossal migration took place, with Anglo-Americans leaving in droves and the newly freed slaves moving en masse to New Afrika. While the United States' economy completely collapsed, New Afrika slowly built itself up with trade from western Europe.
Back in Europe, after all this chaos, the IRA forces managed to secure a breakthrough in Dublin, which they seized and managed to crush the last major UK garrison on Ireland. London was forced to concede defeat, and the new Kingdom of Ireland became the third nation on the British Isles. The United Kingdom was thus abolished in its entirety, and the remnant of its government thus became simply the Kingdom of England for the first time since the 1700s. Ireland took a confederated approach towards its government, with the nation being split into several "Clans" that would elect the High King of Ireland (who would be referred to as simply the King of Ireland outside Ireland itself). Almost immediately, the King of Ireland, an Irish clan leader who had coronated himself King Donal I, made arrangements for meeting with Queen Mary IV, but awkwardly, he died after reigning over an independent Ireland for only around 7 months. And in another ironic twist, his daughter was coronated as Queen Saraid I, leading to the situation that all three nations of the British Isles were ruled by Queens.
Queen Saraid, Queen Mary IV, and Queen Victoria would later meet in Douglas, which had become recognized as a neutral ground between all three nations, and created an informal association between the nations. A formal treaty between England and Ireland not long after achieved a sort of peace in Ireland over the issue of the Protestants in the North who still followed the Anglican Church, that Ireland would recognize these people's right to free worship in a nation that by and large was now mostly Catholic. Scotland in particular also had a division of religion, where many in the Highlands and the Hebrides still followed the Catholic faith.
By 1864, Scotland and England and Ireland, after the settling of the "Irish Troubles", had settled down, and tensions had largely calmed with each other. The friendship between the three Queens of the countries had lead many people to call them the "Royal Coven". This was more in jest than anything else, though. Regardless of this, Scotland still held a good relationship with France. Indeed, even England had started de-escalating tensions with France, seeing any possible conflict with France as being largely ruinous now that the United Kingdom was entirely dissolved. However, even with the British Isles now in a state of peace, the Concert of Europe was starting to steadily fall apart. After the Crimean war had resulted in a Russian victory, the Ottoman Empire had been turned into all but a Russian puppet state, and Austria had gobbled up Bosnia-Herzegovina in a sort of self-compensation for the fact that Russia now effectively surrounded it on two sides. Perhaps more important was the rise of Prussia to prominence in the North German Federation, and with a unification of Germany almost imminent, the balance of power in Europe was in danger of being destroyed beyond repair.