The struggle to belong is the root of many characters’ behaviors in The Mystery Guest. While Molly is continually seen as different, particularly during her time at public school, she has unique resources that allow her to find a fitting niche for herself despite her unconventional quirks. Because she has an advocate in Gran who provides a secure home and accepts her with such love that Molly falls back on her gran’s support even in memory, the protagonist has a solid foundation of acceptance that gets her through hard times. With Gran’s influence, she manages to find a place in society in which she feels happy and valued. At the Regency Grand Hotel, the majority of the other employees now accept her, quirks and all. Because she has found a place in which she belongs, Molly is able to thrive. Lily, however, reminds Molly of herself when she feels out of place and insecure, and Lily’s stress throughout the novel stems from a similar sense of insecurity over where she belongs and who is in charge. When it becomes evident that Molly is in charge, Lily responds to the knowledge that she is in a safe space and begins to speak confidently and assert herself.