The rains finally stop, and the family celebrates spring by fixing up both their abodes, which were damaged by the rain and wind. First they refurbish Falcolnhurst, and then they travel to Tentholm, where they plan to stay for awhile.

At Tentholm, they are dismayed to see how much damage the winter storms have caused: their tent torn to shreds, their provisions useless, and even some precious gunpowder spoiled. However, they are pleased that their new sailboat weathered the storms. The rafts, however, were broken to pieces.

Thinking ahead to the next winter, the father decides to create a place safe from the elements, a strong storage spot to protect themselves and their belongings. Fritz comes up with the idea of a cave. Not finding one, they think to carve out their own cave in the rock abutting their camping site. On the smooth face of the rock, the father marks the dimensions for an opening and they pick away at the hard surface with their axes, chisels, hammers, and shovels. After six days of labor, their progress is minimal, but they do not despair and continue chipping away. A few days later they are rewarded when they notice that the composition of the rock, under the more difficult outer layer, is softer and more yielding to their efforts.

On the tenth day, Jack yells that his axe has made it all the way through the rock. When the father inspects the spot, he can also push his hammer through, as if there were an empty space inside.

The father is about to step into the hole when he smells a noxious gas. Feeling faint, he immediately yells at his sons to run away. Later he explains how poisonous gases can build in cavities where the air has been stagnant for long periods of time. Before they can explore, they must first allow the air to escape. Once this is done, they enter the cave and find what look likes diamond crystals all around. The father tastes the crystals and tells them it is salt, a precious mineral that will improve their animals' diet.

Over the next several days, the family cut windows in the rocks to allow for crosscurrents of air and for sunlight to enter the cave. When they are finished, they have four rooms, complete with a fireplace. They now have a new winter home.