It’s the summer of 1990, and Amy (age 11), Beth (age 9), and Marion (age 6) are in for the family vacation of a lifetime. No, they’re not going Disneyland, Hawaii, or on a Caribbean cruise. No, they’re not flying to Germany to collect pieces of the Berlin Wall.

They will be looking at rocks, though. Lots of rocks. So many rocks.

You see, when your father is a geologist, that’s what you do on your summer vacation (as the author knows from her own childhood road trips with her geologist father). You drive for days to the British Columbia–Yukon border, strapped in the backseat of the family truck with your sisters, fighting over the Gameboy, listening to your parents tell you “fascinating” facts about the scenery, playing the Little Mermaid soundtrack on a loop, and trying not to get elbowed in the face. Doesn’t that sound like a dream vacation? Well, it’s no luxury trip, but it has its highlights—from camping under the stars to wading in natural hot springs to flying a helicopter! And for Amy, Beth, and Marion, the memories they make along the way will last a lifetime. At least that’s what their parents tell them…