The naturalist joins a team of scientists examining the 200 million-year-old fossilised remains of an ichthyosaur, a vast sea creature which was discovered on Dorset's Jurassic Coast. As the skeleton is reassembled, advanced imaging technology and computer animation is used to create a simulation of the sea creature as it would have appeared when it was still alive - the most detailed reconstruction of its kind ever attempted. Meanwhile, forensic investigators painstakingly examine the bones to solve the mystery of how the ichthyosaur died.