"After Ten Years" explains the passage of time. The young boys are now young men, and their parents are very proud. They call the island New Switzerland. Tentholm (now called Rockburg because of their cave-like residence) continues to be their winter home because of its protection from storms. Falconhurst is home in the summer months, close to their cultivated fields and away from the hot beach. Out in Safety Bay lies Shark Island, planted with coconut trees and decorated with a tall lookout tower. They have cleaned the swamp, which now boasts a beautiful lake with a flock of black swans. The African bullfrogs have attained their full size, as large as rabbits, and respond to Jack's call.

Elizabeth and the boys are all in good health. Fritz is twenty-five, very strong and high spirited. Ernest is twenty-three, taller than Fritz and more studious. Jack, at twenty, is as tall as Fritz but more thickly built. He retains his grace and agility. Franz is seventeen and possesses, in his father's estimation, the greatest wit.

Many adventures have occurred over the years, the father writes, but he does not want to tire the reader. However, he does relate one involving Fritz. The boys often went on hunting and exploring trips on their own, so he often lost track of where they were. One day, the whole family was so busy working that they did not notice until almost nightfall that Fritz was gone. They discovered that the kayak was also missing. This worried the father, as Fritz had never before gone on a sea voyage without telling his parents. As night fell, the father sailed to Shark Island, climbed the lookout tower, and searched the horizon. Finally, he noted a small dark spot that slowly grew larger as Fritz rowed his kayak to shore.

Arriving home, Fritz related his adventures, including finding pearls in huge oysters he spied on the floor of a quiet bay. He thought the oysters might taste better than the smaller ones in Safety Bay. So he dragged the bottom and gathered a bag full of them. As he sat on the beach, resting for his return, the sun caused the oyster shells to open. Fritz was surprised to find the round jewels inside.

Although his father reprimanded him for leaving without telling anyone, he praised Fritz for finding a true treasure.