Sisters focuses on the decline of the Lóngshān city-states as the second millennium BCE commences. Environmental issues have come to a head, exacerbated by the farming of marginal lands, overhunting, and massive flooding to the south; these factors contribute to mass migrations.

There is a persistence amongst the ruling elite in their failure to recognise the needs of the peasantry, treating male workers as if they were chattels and women even worse. Sporadic resistance occurs, but the Sisterhood, in league with the Xià, set in motion an epoch-defining plan to overturn the Lóngshān rulers and replace them with an equalitarian society.

Groups of migrants, most from the south, the land of the Yangtze, coagulate around a common purpose and the changing geography, making their way north. Amongst them are the Xià, guided by the Sisterhood, who are ready for confrontation and target the soft underbelly of the Lóngshān.

As the Xià establish themselves in the Yellow River valley, friction grows, culminating in violent conflict and the war to end all wars. Will the Sisterhood prevail?.