American Girl's 2018 Girl of the Year, Luciana, travels to the Chilean desert in this third book in her series.

In her third story, Luciana and her family are headed to Chile for winter break. Luci can't wait to see her cousins - but the reunion doesn't go as planned, and Luci feels like an outsider in her own family. Just then she receives a surprise invite from Claire Jacobs, her frenemy from astronaut training camp, to join her at the Mars habitat in the desert and watch NASA scientists at work. It's an offer too good to refuse, so Luci decides to leave her cousins and give her friendship with Claire a second chance. But what if Luci has made the wrong decision? What if she still can't trust Claire? When disaster strikes in the desert, Luci finds out the truth.