Flynn travels to 1931 Chicago to partner with gangster Al Capone. Lucy, Wyatt and Rufus, meanwhile, team up with the only man who can bring Capone down: federal law-enforcement agent Eliot Ness.

While Wyatt sneaks away from the bunker to face an unbelievable truth, Lucy, Rufus and their former enemy-turned- teammate, Garcia Flynn, chase the Mothership to the Salem Witch Trials. There they must prevent the execution of a headstrong young woman who, it turns out, is mother to one of the most consequential Americans of all time – the yet to be born Benjamin Franklin. When Lucy is accused of being a witch, the team rallies together not only to save Abiah and Lucy, but all the accused women.