Ann, Simon, George, Phyllis, Edvard, and, of course, Nadia head to the polar ice caps of Mars.
It's a bit of a working vacation for them. On the way, they lay transponders and clear a path for future robotic vehicles to follow, and they also make side trips to study unusual mineral outcroppings, despite Ann's irritability over moving away from their polar goal.
Ann and Phyllis, in particular, argue often over the origin and significance of various geological features. Nadia wonders if science is as much a field of study as it is an ideological weapon to attack others.
They stop to install a permafrost water collector because you can't have too much of the stuff.
And so the trip continues. Every morning, Ann and the other geologists spend time collecting samples, and they roll ever northward.
The sand dunes grow larger, like giant ocean waves frozen in time. On one of these giant dunes, their rover's check-engine light turns on, so Nadia goes to fix this issue, letting the geologist play on their mineral playground.
When she's done, Ann invites Nadia to the top of one of the dunes. They watch a Martian sunset, and for the first time, Nadia is consumed by how absolutely alien and beautiful Mars is.
Again, they're northward bound. Now, though, the world looks different to Nadia than it did before, but it's really her perspective on the place that's altered.
Five thousand kilometers later, they finally reach the tip of a polar glacier, but it might as well be a mountain of ice for how huge it is.
They set up the ice mining equipment, and that's that, mission complete.
But for Ann it is not—she wants to travel and study the planet's North Pole, and she claims this might be their only opportunity, especially if the terraformers get their way.
Phyllis, George, and Edvard disagree, so they call it in to discuss the matter with Maya, Frank, and John. After some debating, Ann gets her wish, but Phyllis and Co. decide to linger behind to make sure the ice miner works properly.
They find the North Pole, and Nadia stands at magnetic north. In the sky, the sun circles them.
Nadia thanks Ann for the experience; Ann says someone should enjoy it since if the terraformers succeed in convincing the others, these ice caps won't be there much longer.
Four days later, they return to find George has built a pseudo-Greek temple from cylinders of ice stacked like Doric columns.
On the way back, Nadia understands what Ann has been saying, noticing how much of an impact their small vacation has had on the environment.
They double-check on their permafrost pump to find it's busted from a mixture of extreme cold and lots of water. Looks like Underhill's water issues have been solved.
The closer they get to Underhill, the more closed-mouth Ann gets. Nadia asks her what is wrong, and Ann says, "I want to be out on [Mars] traveling over it always, to study it and live on it and learn it. But when I do that, I change it—I destroy what it is, what I love in it" (3.5.162). Sadness.
Nadia points out that the radiation will eventually destroy them if they don't do anything to thicken the atmosphere. Ann concedes, but notes that Mars will vanish and be replaced by them as a result.