Walt Disney takes viewers on a journey into the history and behaviors of the beasts that lie below the waves. During the show, viewers see how the giant squid from 20,000 Leagues Under the Sea was brought to life with assistance from Kirk Douglas and Peter Lorre, explore the prehistoric ancestors of these beasts through clips from Fantasia, and recall Pinocchio's encounter with the fearsome Monstro with narration by Cliff Edwards reprising his role of Jiminy Cricket.