A clown fish, is overly cautious with his son, Nemo who has a foreshortened fin When Nemo swims too close to the surface to prove himself, he is caught by a diver, and horrified Marlin must set out to find him. A blue reef fish named Dory joins Marlin and complicates the encounters with sharks, jellyfish, and a host of ocean dangers. Meanwhile, Nemo plots his escape from a dentist's fish tank