Liz joins a team of scientists aboard a deep-sea submersible in search of an elusive ocean giant - the sunfish. She discovers how El Nino has effected the sea-lion population and helps with the tagging and tracking of hammerhead sharks.

Liz joins a team of biologists atop a volcano studying the endangered pink iguana. She descends a kilometre into the ocean abyss in search of new species hiding in the dark. She learns about a project studying mutations in marine iguanas.

Liz and the team see the impact humans have had on the oldest islands in the archipelago. Liz descends into a lava cave and meets a man working to protect giant tortoises. She dives to witness the birth of a new island.