One day at the beach, Tom chases Jerry. After Jerry kicks a volleyball at Tom, which he retreats to his Sandcastle, Jerry proceeds to launch a bucket of sand at Tom from a catapult. Tom, not to be deterred, builds a bigger sandcastle equipped with water cannons which he uses to fire at most of Jerry's sandcastle. Jerry survives the onslaught, but fires back with a gelatinous orb of water that washes away Tom's castle. Later, Tom grabs Jerry, stuffs him in a bottle, and throws him out to the ocean. another bottle comes in front of Tom and inside it is an illustration of a dynamite stick, which explodes in Tom's face. At the pier's end, Jerry (who somehow got himself out of the bottle) rescues a dolphin (and plenty of fish) from the netting of a tuna boat.
While the dolphin is showing appreciation to Jerry, Tom shows up to net Jerry, only to be beaten by the dolphin who is now protecting Jerry, making Tom crash into a coconut tree, and five or six coconuts whack Tom's head. Jerry then frolics with the dolphin while Tom is continuing the pursuit with a motor boat and water skis, which ends with Tom going up the ramp, losing the motor and skis as he ascends to the sky and dives into a boat's smokestack. As Jerry and the dolphin surf on a wave, Tom is on a surfboard with Jerry in his sights, but is eliminated by the Dolphin. Soon, Jerry goes scuba diving as Tom without being seen underwater, scuba dives to Jerry's location, capturing him, but the dolphin bites onto Tom's flippers, slingshooting him in the sky and into a painful back flop against the water.
Later, Tom tries a fishing pole to get Jerry off of the dolphin, but the fishing line wraps around the dolphin's dorsal fin and Jerry's legs. The dolphin swims under the ocean wrapping the fishing line around many underwater obstacles until they encounter a sleeping shark, which Jerry ties the line to his tailfin's base. Tom reels in the shark who then eats up Tom's boat, chases him over the ocean, as Tom tries to escape with a jetski, which runs out of gas and sinks until the dolphin and Jerry rescue Tom leaving a depressed shark with no dinner as the pair become friends and return to the beach while riding the dolphin.
- Shortly before Tom goes up the ramp, his swimming top disappears in a close-up shot, but then reappears in the next shot.