A Suspeita is a detective thriller which tells the story of Lúcia, a famous police investigator. 55 years old, she has dedicated her whole life to the professionand commands the respect of her colleagues. All this changes in the course of an investigation. A famouso writer, who was working on the memories of one of the important drug dealers in Rio de Janeiro and whose telephone has been tapped by Lúcia, is murdered. Just as she discovers that she is suffering from Alzheimers, the policewoman becomes object of her bosses' investigation.