In her final months, she finds solace in an artificially intelligent holographic recreation of her late husband Walter, called "Walter Prime." They talk every day, recounting special moments of their life together. But her memory isn't perfect, and Walter Prime can only rely on retellings to piece together what happened. He also talks to other people, including Marjorie's daughter Tess and son-in-law Jon, who move in to take care of her. From all his exchanges, Walter Prime gathers various information on how to play his part, and pieces together a history shared between all the characters that he refers to in his conversations.