"Amnion River" is a visual novel following Lis, a young thief from Whitecalder trying to rekindle her long-lost passion for painting, as she deals with her declining health and recurring nightmares. One day, a nameless young girl with unusual, reddish skin, snow-white hair and no clear memory of her past enters her life seemingly out of nowhere. Lis decides to take her in and names her Clair, a name she vaguely feels befits her perfectly.
As the struggling Lis takes care of her three-legged dog, Toni, and the mysterious Clair, her condition worsens, and she slowly begins to lose touch with reality. Knowing she doesn’t have much time left, she decides to return to her horrid past to find answers about the mysterious death of her dear older sister, Leonore, fourteen years ago.