Tom and Jerry are in a fishing boat. Jerry has just become Tom's slave, and is working hard rowing the boat, while Tom relaxes. Tom orders Jerry to drop the anchor, and they both get ready to dive to spearfish. Tom tries to hit Jerry with the spear, but Jerry tries to escape by jumping into the ocean, and Tom chases him. Tom tries to hunt some seafood, including a pufferfish and a lobster. However, Jerry jumps onto a seahorse to stop him, by scaring the pufferfish. Tom attempts to catch the seahorse with a lasso made out of seaweed, but the seahorse is too strong for him and drags him along the seabed, hitting the coral and many seaweeds, which makes him look like a mermaid. Later, he encounters a very amorous octopus gentleman named Morizzio, who thinks Tom is a lady. Morizzio wants to date Tom, and they end up getting lost in the sea. Later, Jerry meets a fish who loves him, and he flees.