The following version of the book was used to create this study guide: Larson, Erik. The Splendid and the Vile: A Saga of Churchill, Family, and Defiance During the Blitz. New York: Crown, 2020.

On May 10, 1940, during World War Two, Winston Churchill was made Prime Minister of Great Britain. He had a somewhat eccentric personality but he was loved by the general population and his skill as an orator soon demonstrated his ability to rally the citizenry and boost their morale. Sure that German invasion was imminent, and disheartened at the possibility of French capitulation to the Germans Churchill bolstered the Royal Air Force (RAF) to prepare to fight the German Luftwaffe. Churchill was also convinced that the Allies would need the help of the United States to win the war and set about trying to convince President Roosevelt to join the conflict in support of the British. Churchill appointed various people to work on technological advancements and to increase aircraft production. With the war going poorly in France, British troops were forced to evacuate the continent at Dunkirk.

While his team focused on investigating German air navigation technologies, Churchill continued to focus on France and the United States. France eventually capitulated to the Germans. Churchill never wavered in his determination to fight on but needed American support more than before. He was determined to keep the French naval fleet out of German hands and the British navy eventually had to make the difficult and uncomfortable decision to fire on the French navy in order to do so. As the Germans moved further into French territory, the British prepared for an increase in air raids. Luckily, their efforts at increasing aircraft production to strengthen the RAF proved very successful. Hitler called for an all-out aerial assault on Britain and believed the end of the war was imminent.

Luftwaffe attacks against Britain began in August, but the RAF was stronger than the Germans had anticipated. The aerial fighting escalated and major civilian centers like London and Berlin started to be targeted by both sides. Meanwhile, Churchill's daughter Mary enjoyed life in the country but longed to take a more active and contributing role in the war effort. In Germany, a top Nazi official named Rudolf Hess hatched secret a plan to try to negotiate peace with Britain by using the Duke of Hamilton as an intermediary. A major Luftwaffe attack on London was planned for September 7.

Attacks continued throughout the fall. Despite the devastation in London, the RAF was overall proving to be a formidable opponent that the Germans had underestimated. It began to be clear to them that the war would continue throughout the winter. At the same time, Hitler decided to invade Russia, splitting the focus and strength of his military. A major attack on Coventry on November 14 was devastating to the city. Churchill continued to ply Roosevelt for aid and the President eventually came up with the Lend-Lease Act which would allow the United States to support Britain without joining the war or violating existing American neutrality laws. Aerial battles continue with a brief unspoken truce over Christmas.

In January 1941, Harry Hopkins arrived in Britain as an emissary from Roosevelt. After seeing the reality of the war effort, Hopkins told Churchill that he will advocate for America to support Britain in this endeavor. Luftwaffe attacks continued to escalate, targeting government buildings in London. Churchill was impatient over the slow movement of the Lend-Lease Bill through the American government. Meanwhile, Mary Churchill felt the reality of the war as she danced in London only to discover that a club she had planned to visit had been bombed. Hopkins as American emissary is eventually replaced with William Averell Harriman, who eventually became a key presence in Churchill's entourage throughout. Upon meeting Churchill, it became clear to Harriman that the prime minister would not surrender but that he needed American support to win the war.

Britain suffered losses and defeats in the war's other locations such as North Africa, the Middle East, and the Balkans. Meanwhile, love blossomed between Mary and a suitor named Eric; they became engaged despite her family's reservations. She eventually broke off the engagement. Harriman began a romantic affair with Churchill's daughter-in-law Pamela, whose marriage was in shambles. Britain's losses prompted the government to hold a referendum on Churchill's handling of the war. He won a nearly unanimous vote with only three ballots cast against him.

Churchill's one year anniversary of being in office was marked by the worst aerial attack on London. The same night, Rudolf Hess landed in Scotland after a secret flight across the Atlantic. He was promptly captured and treated as a potential war criminal. Air raids against Britain dissipated after May 1941 but as readers know, the end of the war would prove to be many years away. By the end of Churchill's first year in office, it was clear that he had succeeded in raising the morale, spirits, and courage of the British people. In early December 1941, the United States joined the war after the Japanese attacked Pearl Harbor. Churchill was confident that the Allies would now win the war.

In the book's epilogue, Larson writes about what happens to various people in the book after the first year of Churchill's government. Mary became an anti-aircraft gunner. Pamela and Harriman continued their relationship for a while and reconnected decades later to rekindle their romance. They eventually married. The various German leaders who appeared in the book either committed suicide or were convicted at the Nuremberg trials. Churchill continued to capture the hearts and minds of the public as their beloved war-time leader, even though the people sought a new leader for the recovery period after the war.