Jack leaps into the water to rescue his son from the unseen menace and they swim to the safety of the shore where Gideon has found a bottle. Back at Granite House a message is pulled from the bottle‹written by a fellow castaway on the island! Jack, Herbert and Gideon set out on a test voyage in their boat to locate the castaway. They find his well-stocked camp and gather up supplies as no one is in sight. Mr Ayrton soon makes an appearance and Herbert convinces his father to take him back with them. Meanwhile, Joanne, while out by herself gathering plants, is overcome by Nemo's gas devise and falls unconscous. When Neb goes to search for her, he too is overcome but before he collapses, he sees Nemo approach. Back in Nemo's lair, Nemo posions Neb, making it appear to be from a snake bit. Harding later finds Neb's body and a memorial service is held, with Harding biding a tearful farewell to his dear friend.