At Goo Lagoon, SpongeBob and Patrick are sunbathing. SpongeBob remarks on how cool Larry the Lifeguard is, and SpongeBob fantasizes about how "cool" it would be if he was a lifeguard, but Patrick does not agree, disliking lifeguards. SpongeBob then says that he is "just as cool as Larry." SpongeBob claims that if he is not as "cool" as Larry, that he will be struck by "a flying ice cream truck." An ice cream truck falls from the sky and he quickly says "AND LIVE!" He then gets struck by the ice cream truck and Larry helps him up and notices vanilla ice cream on his nose. Thinking that it is sunscreen, and that therefore he is a lifeguard, he offers SpongeBob to help him with his lifeguard duties.
As a lifeguard, SpongeBob becomes very popular and does many fun activities. However, when Larry hears Bill drowning and saves him, SpongeBob realizes that being a lifeguard is much more than giving ice cream and sitting in a tower, but that it also means that he has to guard other people's lives. Larry suddenly leaves for a tanning booth, leaving SpongeBob, who cannot swim, in charge of the beach. SpongeBob then imagines all the fish dead in a graveyard in the goo, and then alerts all the fish to an "emergency" that is not even going on. When everybody asks, confused as to what the "emergency" is, SpongeBob, forgetting that sharks are sea animals too, improvises and states that the "emergency" is a shark attack. A shark family then says that they are the ones he is referring to. Then he announces that there is a sea monster, but a sea monster then emerges from the crowd, slapping SpongeBob with his tail fin after explaining how impolite he is to sea monsters and everybody then knows that there is no emergency.
SpongeBob begins panicking when he sees everyone playing in the water in a dangerous way, such as people splashing each other, people water skiing on top of each other, two kids playing with a ball inside of Billy the killer whale's mouth, and Frank throwing Scooter into a rock. SpongeBob then lures everyone out of the water with ice cream. After they eat it, he tells them that they now have to wait one hour before going back in the water and binds them with police tape. Thinking that everyone is safe, SpongeBob settles down to relax. However, the beach guests get upset at this and one fish states that Larry is a better lifeguard than SpongeBob is. SpongeBob announces that he gave them ice cream, and Larry never did. However, after emerging from the bathroom, Patrick mistakenly looks for ice cream after SpongeBob says "ice cream" through a megaphone, crosses the tape after he sees the words on it as "ICE CREAM," when it really is "DO NOT CROSS," and goes into the water, where he gets cramps and starts drowning. When other fish get alerted to this, SpongeBob initially refuses to believe that someone is drowning, but he eventually sees Patrick and tries to find a way to save him without going in the water. He reaches Patrick using a boatmobile he "borrowed" from the parking lot, but Patrick destroys it and they both start drowning. Larry then comes back and "saves" them from the ankle deep water. Larry asks if SpongeBob is a real lifeguard, to which SpongeBob replies "No." At the end of the episode, Larry is seen teaching the two how to swim, and they both get butt cramps, and Patrick still does not have his ice cream, much to his dismay.
Even though the setting of the episode and the entire show is under water, Goo Lagoon is depicted as a body of water under water, and no one in the series ever references this fact.
When Larry lifts the board with fish on it, two of them fell off of their faces first.
The old man who Larry tells to leave (and who is implied to be Larry's father) reappears as a beach person in a later scene.
When SpongeBob raises his arms to call the people for ice cream, he never lowers his arms as he gives it to them.
After everyone at the Goo Lagoon go back into the water, two shark fins are swimming around a beachgoer despite the fact that the only sharks mentioned were an actual family of them, meaning that SpongeBob was right about there being sharks.
Although, it might have just been the shark family swimming like real sharks.
When the crowd is looking up at the lifeguard tower when SpongeBob calls everyone out, Annette does not have any hair.
It is not Evelyn, however, because in the next shot and for the rest of the episode, Annette has her hair back.
SpongeBob's nose changed color every time Patrick hit him with the anchor.
When SpongeBob sees that Patrick is drowning, he breaks the lens of his binoculars, but the lens are back after Patrick finishes shouting.
When Patrick comes out of the Port-O-Head, there is toilet paper sticking out of his shorts. When he gets near the lagoon, it is gone.
In the scene when Larry saves Bill, a crowd of fish are worried.
However, Bill was in the crowd.
When SpongeBob hands out ice cream, White Fish is shown with a pink ice cream. In the next shot of him, the ice cream is white.
When SpongeBob hands out ice cream, Nat Peterson is shown with a red popsicle. In the next shot of him, the popsicle is blue.
Nancy Suzy Fish is seen leaving with Larry for his tanning, but is again seen later sharing a hot dog with Gus in the parking lot.
Since Goo Lagoon is a lagoon, SpongeBob would not be able to drink all of the water in Goo Lagoon as more water from another body of water next to it would flow in.