Adrift on the ocean, Jean, Nadia, and King are once again rescued by another vessel — a mysterious submarine commanded by Captain Nemo and his first officer, Electra. The children are kept aboard the submarine for three days while Nemo and his command crew pursue an enemy submarine (the same "sea monster" that wrecked the Abraham). Eventually, Jean, Nadia, and King are released from the submarine and they set off into the sky on Jean's newly revamped aircraft. Before leaving, the children learn that the submarine is known as the Nautilus.