The ichthyosaur Ophthalmosaurus breeding ceremony is the main event of the episode, but sharks and other predators, including the pliosaur Liopleurodon, are on the hunt. The opening portrays a Liopleurodon snatching a Eustreptospondylus (dinosaur) from the land, but there is no evidence of this ever occurring (according to the producers, they were influenced by similar attacks by killer whales on land creatures, such as sea lions). A pod of Ophthalmosaurus arrive from the open ocean to give birth. Many of the babies slip out successfully. But when one mother has trouble giving birth, a pair of Hybodus sharks go after her, but are frightened off by a male Liopleurodon, which eats the front half of the Ophthalmosaurus, leaving the tail to sink down. Meanwhile a Eustreptospondylus swims to an island. It discovers a turtle carcass and must fight another Eustreptospondylus for it, though the fight really consists of them roaring at each other. Later during the night, a group of horseshoe crabs gather at the shore to lay their eggs, which attracts a flock of Rhamphorhynchus (pterosaur) in the morning. However two or three are caught and eaten by a Eustreptospondylus in the morning. While the Ophthalmosaurus juveniles are growing up, they are still hunted by Hybodus, which in turn, are prey for the Liopleurodon. While the male Liopleurodon is hunting for prey, he is encountered by a female Liopleurodon, and after biting one of her flippers, she retires to escape. In the end of the episode, a typhoon kills many animals, including a Rhamphorhynchus, and washes the Liopleurodon ashore. He is then suffocated by his own weight and is eaten by a pair of Eustreptospondylus. The episode, however, ends on a more positive note, as it shows that the juvenile Ophthalmosaurus have survived the storm, and are now off to live and breed in the open sea.