The Batavia Queen arrives off Krakatoa to find the island shrouded in thick smoke. It clears when she anchors off the island, and the Borgheses ascend in their balloon while Rigby descends in his diving bell. The Borgheses quickly discover the wreck of the Arianna and guide the Batavia Queen and the submerged Rigby to it. Immediately afterwards, the motor driving the propeller that allows them to steer their balloon fails and they careen helplessly over Krakatoa and into its active crater. They jettison the useless engine and propeller into the crater's lava lake to reduce weight and finally are blown clear of the crater by a volcanic explosion which sets their balloon afire. They drift away from the island, leap into the sea, and are rescued, but the fire destroys the balloon.