Two Russians throw a mechanical shark overboard into the sea. Meanwhile, Misterjaw has found a new home: a resident's expensive swimming pool. When the owner comes to swim with his rubber horse, Misterjaw leaps out of the water and scares the owner and the rubber horse half to death. All seems calm until the owner rents the female, mechanical robot fish to clear up the matter. A swordfish attacks the robot and bends his sword. When the robot attacks a sea dragon, he finds himself outclassed. Now, Misterjaw attempts to "train" the shark to catch and eat tuna with humorous and disastrous results.