Marjorie (Lois Smith) is an elderly woman who lives with her daughter (Geena Davis) and son-in-law (Tim Robbins). Marjorie’s mind has started to drift as she’s gotten older, so to help, she’s begun talking to a holographic reproduction of her husband, Walter (Jon Hamm). The creation — referred to as a “Prime” — is a software-driven blank slate that can take on the characteristics and nuances Marjorie remembers about her husband, even if some of them aren’t exactly true. As other family members talk to Walter Prime, it becomes clear that the family has been haunted by unspoken secrets and tragedies they’ve never really dealt with.