After losing a shoe and seeing a street sign has gone missing, high school student Violet Bookman begins an Instagram account to try to document everything strange that's disappeared. When she's not riding around town on her bicycle, she likes to spend time with her twelve-year-old neighbor, Nanako, a cellist who invents her own board games.

But when Nanako's cat, Mr. Business, goes missing, Violet searches all over town, from British Soldier Field—where the British soldiers once disappeared in the woods in the 1760s—to the envelope factory to the garbage dump to the clock tower.