The story of Anna Grieve and her fragile older sister, Esther, begins in Russia in the 1880s. The vicious persecution of Jews has come to such a point that the girls' mother makes the decision to send her children to Winnipeg with her wealthy employers. Her intention is to join them, but the sisters never see their mother again. Frightened and cut adrift, each girl reacts differently to her new family in North America. Esther's beauty and glamorous lifestyle hide the fact that she may be losing herself to mental illness. Anna, who is the only one who knows that her sister is suffering, spends her life torn between taking care of her and escaping her. As soon as she can, Anna leaves for New York and makes a new life as a women's rights activist with an illegal contraceptive business in Manhattan, but her bond with Esther never loses its grip. When Anna receives the unexpected news of Esther's possible suicide on "If Day", an unusual day in WWII history when a simulated Nazi attack took place in Winnipeg in order to raise funds for the war effort, she immediately returns to Canada. Only she can piece together what really happened all those years ago in Russia, why their mother never came for them, and what role "If Day" might have played in Esther's untimely death.