The movie opens above the high seas with a lightning storm is brewing and raging. A group of jolly pirates are sailing on their ship, and all of them are scared of the storm. Meanwhile, the pirates’ brave captain, Red Pirate Ron, who speaks in a language only understood by his parrot, warns his pirates to lower the sails.
After that, the movie continues with Tom and Jerry traveling aboard the same pirate ship. It is soon revealed that Ron is searching for the “Lost Treasure of the Spanish Mane.” By chance, a wave carries the map to the treasure aboard. Tom hides the map, but is warned by the ghost of the Spanish Mane’s captain, Don Diego de Clippershears, that if the map is not returned to the ocean by sunset, a curse will begin.
At one point, Tom and Jerry escape from a giant squid by using a cannon. The ship is then attacked by Ron’s brother, Blue Pirate Bob, who also speaks with the help of his parrot (with credit for the attack due to Jerry). Bob’s crew manages to steal the map, but Ron retrieves it and shoots down his brother’s ship. Ron’s crew celebrates and Tom is given seafood as a treat. Tom gives Ron the map, who begins examining it. Up in the rafters, Jerry copies the map onto his bandanna.
The sun sets and the ghost appears as a crew of skeleton pirates. Ron’s crew abandons ship, and their lifeboat lands on top of the giant squid that Tom and Jerry fought earlier. Angry at Tom for not warning him about the curse (not knowing that he can’t talk), Ron expects him to row all the way to the island where the treasure is buried. Tom, however, leaves Ron’s men stranded and takes only himself and Jerry (who has the map on his forehead) to the island.