How to go from modern Washington to distant Chicago in 1893? For Kate, the impossible has become real. It turns out that her grandmother’s strange medallion is nothing more than the key to the headquarters of CHRONOS, an organization of time-traveling historians from the future. Kate soon discovers that reality has changed and her parents no longer exist, and she is only alive thanks to the protection of the key. Someone killed Kate's grandmother when she was in the nineteenth century. A girl must travel into the distant past and figure out how to prevent terrible consequences. But if everything works out, the guy she likes will never remember her again. Will her movements affect the fate of the whole world?