Ellie's scientist grandfather has discovered a way to reverse aging, and consequently has turned into a teenager--which makes for complicated relationships when he moves in with Ellie and her mother, his daughter.

When, in the process of testing his newest time machine, Professor von Volt accidently brings a triceratops, Helen of Troy, Attila the Hun, Charlemagne, and Christopher Columbus to present day New Mouse City, it is up to Geronimo and his friends to return them all to their own times and places--without being eaten by a T-Rex or skewered by Trojan warriors.

A biographical novel in verse of seven girls from different time periods who used math to explore the mysteries of the universe and grew up to do innovate work that changed history.