It is a sunny day and SpongeBob is taking Gary for a walk when he hears a meow from nearby. He thinks that Gary wants something and after they hear another meow Gary drags SpongeBob in the direction of the meow. SpongeBob then sees an unhappy looking stray snail that is afraid of him but tells them that he will not hurt them and picks them up. He and Gary decide it would be best to take the snail back to his house and name it "Señor Poopus".
After SpongeBob takes the snails home, Señor Poopus immediately becomes happy and gets along very well with Gary. Patrick then arrives and SpongeBob explains how he found the stray snail and decided to nurse it back to health. Hearing this, he tells SpongeBob about the abandoned baby snails. Patrick shows SpongeBob the baby snails under the bridge and, sure enough, he finds them crying. After taking them home, SpongeBob reads a book about snail care, reading out that they must be kept warm at all times. Patrick suggests putting them in his mouth since it is warm. But SpongeBob suggests a better idea. He puts them under a heated blanket which has the temperature set for snails, and gives them milk he decides to be the perfect temperature. Patrick states that he will be leaving but SpongeBob is too busy and happy feeding the baby snails to notice that Patrick is leaving or even talking to him, which causes Patrick to leave crying. Not long after, another snail then bursts in and walks over SpongeBob right to the babies, and SpongeBob then believes she is the mother.
Patrick later comes by telling SpongeBob that since he is now taking care of snails, he told a stranger he met that found a stray snail about it. The stranger thanks SpongeBob for taking the snail, while Patrick tells SpongeBob that he did something really important in an attempt to becomes friends with SpongeBob again, but once again SpongeBob is too busy to notice him, leaving him hurt and angry. Later, another random guy drops off a stray snail, saying, "Thanks, snail guy!" much to the confusion of SpongeBob. Not long after that, there is a whole line of people waiting to give SpongeBob their snails, and SpongeBob eventually ends up with tons of snails.
Meanwhile, Mr. Krabs is upset that SpongeBob is missing work because he has to take care of the snails, albeit not knowing the reason why. He asks Squidward why SpongeBob is not here, but Squidward also does not know why. Mr. Krabs states that since SpongeBob is not around, Squidward will have to do both the cashier and fry cook jobs himself. When Squidward strongly objects, Mr. Krabs states that it is very simple and easy and that "any idiot could do it", leaving Squidward upset and running both jobs while Mr. Krabs goes to find out why SpongeBob is not at work.
Back at SpongeBob's, he realizes that the snails are getting slime everywhere and decides to use the toilet brush and bath curtain to cover himself from the slime.
When Mr. Krabs comes to see SpongeBob, he initially mistakes SpongeBob for a girl because of the toilet brush wig and bath curtain dress, and, believing that he is at the wrong house, starts to flirt with him. However, once he mentions SpongeBob, SpongeBob says "Hi, Mr. Krabs." leaving Mr. Krabs in shock and asking him why he is dressed like a girl. At this point, it is clear that SpongeBob is too deluded by and attached to the snails to give sensible replies. He then asks SpongeBob why he is not at work, and SpongeBob replies that he is taking care of the snails, apologizing and saying that he will try to come to work tomorrow. Mr. Krabs is angry at the "try" part of the sentence and attempts to berate him, but SpongeBob is too distracted by the snails and shuts the door on him, leaving Mr. Krabs shocked and hurt.
Later at night, Squidward comes home sneezing believing he has a cold. When he wakes up the next day however, his face is swollen and he sees all the snails, revealing that he is allergic to snails and leaving him angry. He decides to take matters into his own hands and goes to his snail-covered front yard asking SpongeBob to get rid of the snails, asking how many there are anyway. SpongeBob does not comply to the former, but counts 258 snails, leaving Squidward furious.
Back at the Krusty Krab, Squidward is angry that customers screaming at him while also having his allergy so he quits, much to the dismay of Mr. Krabs, who realizes that he must run the restaurant himself. However, Squidward does not care and repeats Mr. Krabs's words of "Any idiot could do it", leaving Mr. Krabs upset once more.
A hurt Patrick soon visits thinking to disguise as a snail to live with SpongeBob. SpongeBob comes out and asks him his name. He says "Patrick", but immediately changes it to a meow and SpongeBob names him Patrick anyway. He succeeds in entering the house, but when he sees all the snails, he tries to escape, only to fail and be caught by SpongeBob, saying "Meow help!"
The police go to SpongeBob's house and knock on the door trying to take away SpongeBob's snails once again believing him to be a female, but after recognizing him and trying to convince to get rid of the snails, he simply says "No thank you, please" and shuts the door on him.
Back at his house, Squidward is on the phone with the police, furious that SpongeBob said "No thank you, please" and questions what it even means. The swelling gets worse and the phone's handle gets stuck in Squidward's body, while the rest of the phone gets stuck when he goes to see what is going on at the window. He complains that it has to stop.
SpongeBob tells the snails that "the bad men" want to take them away from him, having built and electric fence to keep them out. Just then, a man arrives with the police and asks for SpongeBob, needing a reminder from the police that he is male. Introducing himself as Bob Barnacle, he explains to SpongeBob that all the snails escaped from a hole in the fence of his sanctuary and that what SpongeBob is trying to do is great but not enough and at the sanctuary, there will be several people willing to help the snails and they will be properly loved and taken care of. At this moment, SpongeBob recovers his senses and gives up the snails to the sanctuary, first giving him Señor Poopus before Bob refers to him as "Esmerelda" and asks SpongeBob what he named her with SpongeBob nervously saying "Señor Poopus".
Later all the snails are shown in the police truck. SpongeBob says goodbye to all the snails as well as Señor Poopus before correcting himself by saying "Señorita Esmerelda". Patrick says goodbye to SpongeBob and SpongeBob says goodbye to Patrick before realizing that the Patrick snail is Patrick and chasing after Patrick, telling him not to worry as he will adopt him.
In the scene where SpongeBob and Patrick pass under the bridge, in the storyboard version, there is a piece of coral, but in the final version, it is replaced with a piece of kelp on a rock. Also, the bridge is brick in the storyboard, but rock in the final version.
After when SpongeBob says, "I'm gonna take 'em [the snails] home and feed them." In the storyboard version, there is a piece of kelp next to Patrick, but in the final version, it is not there.
In the scene where SpongeBob takes care of the baby snails in his kitchen, in the storyboard version, on the The Big Book of Snail Care's cover, there is a snail that is looking towards SpongeBob, but in the final version, it is away from him. The spine and back of the storyboard version have snail images, but the final does not. Also, the final version of the Powdered Snail Formula has an image of a snail on the box, but in the storyboard version, there is no snail. Patrick is also closer to SpongeBob in the final version than in the storyboard version. In the storyboard version, the final setting of the electric blanket shows the front side of four snails, but the final version shows a silhouette of the side of one snail. The basket in the storyboard version has a different pattern than in the final version. The snail suckle is upwards in the storyboard, but downwards in the final.
It is revealed that Squidward is allergic to snails, although there is only a reaction if there are many snails. He can stand a few, which is why he was never allergic to Gary the Snail, but probably one of the reasons that he didn't like Gary in "I Was a Teenage Gary." And despite this allergy, he once adopted a pet snail of his own in the episode "The Great Snail Race."
For the second time, Mr. Krabs is shown flirting with a male character that looks like a female. The first time was in "That's No Lady."