Mother prepares an oyster stew for the family, but they're inedible. As she's tasting the meal while cooking, she consumes enough poison to collapse and fall into a coma.
Ernest, Franz and Marie hike to the north side of the island to search for a wedding anniversary present for their parents. They find a chest from their shipwreck which may contain a valuable artifact.
Johann cancels lessons when Ernest, Franz and Marie complain that school is useless on the island. But when Johann tells them they can have two days to do whatever they want, they find out that math and science can be useful after all.
Ernest and Franz rescue a castaway they find floating offshore on a couple of barrels. The castaway says he has a map of the island, and insists that there is a settlement beyond the waterfalls.
Traveling to South Island to investigation a signal, the Robinson family discover a skeleton in a cave. Ernest is injured from a fall. But the real Terror was yet to be revealed as Soldier Ants were swarming towards them.
Franz and Ernest find an abandoned pirate camp while exploring the island. Franz also finds a treasure map at the camp, and becomes obsessed with finding the treasure, while neglecting his usual duties.
Ernest finds a pregnant wild goat in the jungle and brings her back to the treehouse. Marie is eager to witness the upcoming birth, but Mother worries that something will go wrong.
Ernest builds a boat from salvaged shipwreck timber and sets off to the open seas, in hopes of finding help for his stranded family. But he unfortunately loses his compass and becomes lost at sea.
The family's pet leopard, Ulysses, has grown too large and dangerous to keep around. But when Franz and Ernest release him deep in the island's jungle, they find he is too domesticated to survive on his own.
