Before I Forget (2021)

When Pascual Leon, a retired bachelor of 65, is diagnosed with Alzheimer's, he finds the perfect excuse to collect on an old debt: to kill off, one by one, those responsible of a terrible crime. This sets off an investigation by a young female officer, to whom Pascual dedicates each of his killings. She must reach back into her childhood memories to connect the links between these murders and get to the truth. While he forgets, she must remember.