Nine-year-old New York City twins Emma and Simon visit their grandmother for a sleepover and shake a snow globe from her collection. Immediately, they are transported to Coney Island in 1928, right in front of the world-famous Cyclone roller coaster. When the twins come face-to-face with their great-grandparents, they must make sure that the pair meet on the Coney Island trolley. If things don’t go like the family legend, the twins may never be born.
Emma and Simon shake another enchanted snow globe on their latest sleepover with Nana. This time, they’re transported to Philadelphia in 1915 and witness the Liberty Bell making its last historic transcontinental train ride to San Francisco. They soon realize that their Great-Great-Aunt Lucy was one of the schoolchildren who signed the petition bringing the Liberty Bell to California. When trouble brews, will the twins and Aunt Lucy be able to help the Liberty Bell get back on track?