During World War II, as Adolf Hitler's powerful Wehrmacht rampages across Europe, the Prime Minister of the United Kingdom, Neville Chamberlain, is forced to resign, recommending Winston Churchill as his replacement. But even in his early days as the country's leader, Churchill is under pressure to commence peace negotiations with Hitler or to fight head-on the seemingly invincible Nazi regime, whatever the cost. However difficult and dangerous his decision may be, Churchill has no choice but to shine in the country's darkest hour.