As Europe enters a new century of unprecedented prosperity, many beliefs compete to shape the coming years. Pacifism, nationalism, socialism, and other ideas offer a vision of new utopias while older institutions and beliefs struggle to maintain order and relevance.

Four young Parisians are caught up in the sweep of historic events that affect their actions as they try to influence the world they have inherited. Their ideals soon clash with older notions more persistent and powerful than imagined.

As the century progresses, the continent face crises from old tribal tensions,...