The nuclear bomb dropped on Hiroshima heralded the dawn of a new era. Its detonation not only killed over 100,000 people but also signified both the final chapter of World War Two and the beginning of the nuclear age. Armed conflict, international politics and the security of all mankind would never be the same again. Through a detailed retelling of the events before, during and after the dropping of the bomb, this film unravels the compelling story of one of the 20th century's defining moments and reveals the far-reaching consequences of the explosion, both in Hiroshima itself and for the world at large. From the rooms of the world's most powerful leaders, both Allied and Japanese, to inside the planes sent on the fateful mission to the devastated streets of Hiroshima in the hours after the attack, it explores the crucial moments, the key locations, and the pivotal players.