In 1898, in Southern Finland, Amanda Aaltonen arrives at the island sanatorium of Seili, a final destination for women with behavior deemed problematic. She is a rebellious young woman with a spirit of anarchy and adventure and, having lost her freedom, must adapt to a new life in confinement. But after numerous failed attempts to escape, she eventually resigns herself to her fate. She forms close bonds with other patients and falls in love with a local fisherman, but the divide between the inmates and the islanders is insurmountable, and everything seems to point toward a tragic end.