In the summer of 1878, the Ludwig Zirkus arrives on Nordstrand in Germany, to the delight of the island's people. But after the show, a Hundred-Year Wave roars from the Nordsee and claims three young children. Three mothers are on the beach when it happens: Lotte, whose children are lost; Sabine, a Zirkus seamstress with her grown daughter; and Tilli, just a girl herself, who will give birth later that day at St. Margaret's Home for Pregnant Girls. After the tragedy, Lotte's husband escapes with the Zirkus, while she loses the will to care for their surviving son. Tilli steps in, bonding with him in a way she isn't allowed to with her own baby, taken away at birth. Sabine, struggling to keep her childlike daughter safe in the world, forms a complicated friendship with Lotte. But the mothers' fragile trio is threatened when Lotte and her husband hatch a dangerous plan to reunite their family, and Tilli and Sabine must try to find a way to pull them back to reality.