In 2008 South Side Chicago, ten-year-old Montgomery "Monty" Carver's hunt to find the origins of a mysterious golden key leads him to discover the rich history of his community.

Legend says that an eccentric millionaire hid a treasure somewhere inside the legendary "White City" at the 1893 World's Fair in Chicago. Elsa and Liam have reason to believe that treasure holds the key to finding Elsa's grandfather who disappeared mysteriously over a year ago. The kids decide to break out the duct tape and twist ties to reassemble the World's Worst Time Machine. They're on the hunt! Liam and Elsa are not the only time travellers...