Having left the Mediterranean Sea, Zak and Rory continue their adventures and travels towards New Zealand. Along the way they meet Zak's family and a new friend, Rodger the Leatherback Turtle, and encounter a huge natural disaster. The duo and Rodger help a human sailing family fight a monster from the deep. They assist them in getting to safety on a nearby island. Having survived a natural disaster and fighting monsters from the deep, the duo leaves to fight for Zak's life against the most skilful and the worst of monsters they encounter--humans. Zak is relentlessly chased by whalers who want to kill him. However, Rory saves the day so he and Zak can continue on to New Zealand.