The Diary of Margaret Evans tells the story of Greta, who helps her father catalogue the estate of Mulberry Hill. While alone at Mulberry Hill one day, Greta begins to hear footsteps coming from upstairs. Thinking it is her younger brother, Tim, Greta investigates. Searching through each room, Greta comes upon a room and is surprised to see a ghostly figure of a woman standing by the window. The ghost pleads with Greta to ‘help me find her’. As she begins to investigate more into Mulberry Hill, Greta determines that the ghost of the young woman is that of Margaret Evans, who died nearly seventy years ago. Learning more about Margaret, Greta receives some help from one of Margaret’s oldest friends, Miss Hannah Whittington, who reveals answers and knowledge of a time capsule buried at Mulberry Hill Estate. Upon finding the time capsule, Greta begins to ask more questions, especially the resemblance of past employee Jas Cooper and Jimmy, the caretaker’s nephew. After an accident, Greta finds herself in an extraordinary experience and wakes up in 1939. As she talks with Margaret, her brother Bert and friend Emmett, Greta learns more about Margaret’s life. As she awakens back in 2009, Greta begins to have the strongest sense of déjà vu and remembers a diary Margaret kept in her room at Mulberry Hill. As the past haunts the present, Greta along with the help from Jimmy, begin to unlock a mystery that has been forgotten for over seventy years.