Claire and Jamie reunite with the Lallybroch and MacKenzie men as they train for war. Jamie’s power struggles with Dougal and Claire’s personal battle with her memories of WWII weigh upon them, but new, helpful information comes to light when a young Englishman named William Grey pays a surprise visit to their camp.

Jamie relies upon Claire's knowledge of history to lead the Jacobite army into a crucial battle. Claire is reminded of the true cost of war as she attends to the dead and dying.

Jamie works to divert the Jacobite army away from imminent slaughter. Claire tries to provide comfort to a sick Alex Randall who shares an unusual plan to save the mother of his child.

In the present, Claire reveals the truth to her daughter, Brianna. In the 18th century, Jamie does everything he can to save his loved ones as the Battle of Culloden begins.