In this third book in the Astrid the Astronaut chapter book series, Astrid is torn between her best friend and arch-rival!The Shooting Stars and Petite Picasso groups are working together on a combined STEM and art project--which means BFFs Astrid and Hallie finally get to team up! But Astrid's excitement doesn't last long when they are grouped with her arch-nemesis: Pearl. And what's worse, Hallie actually agrees with some of the ideas Pearl has for the project. Isn't she supposed to be on Astrid's side? Can Astrid, Hallie, and Pearl learn how to work together and create a project that's out of this world?