Duality(2023)

After their mother suspiciously dies, Gemma (25) and Charlotte (23) are left to raise their younger brother alone in their small, isolated cabin in Alaska. While they remain financially struggling, their estranged, wealthy father falls into a coma. Gemma, the oldest and next to kin, would be faced with making the decision to pull the plug or not. However, Charlotte, lusting over the potential inheritance, is determined to prove she should be the one to decide because Gemma is mentally ill.