The Conspiracy of Jellyfish Beach

The Conspiracy of Jellyfish Beach (海月浜の陰謀) is the 378th chapter of the manga and the only chapter of the Jellyfish Beach Arc.

A relaxing day at the beach sees Akane once again trying to learn how to swim. Some local residents see her thrashing about in the water and tell her she is the 10,000th girl who can't swim well, and therefore wins a special swimsuit that will allow her to swim like a pro.

One Day at the Beach
Akane, dressed in a swimsuit, snorkel and flippers, declares that they should go swimming. When Akane goes into the water she is also wearing a Swim ring and has Nabiki looking over her. While Akane "swims" with Nabiki holding her hands, she (Nabiki) asks Akane if she's having fun yet since it's just water.

Just then Ranma (in his female form) appears and is chasing after Happosai who has stolen a watermelon. Ranma attacks Happosai with a wooden bat, which gets the watermelon out of Happosai's grasp. However, the rest of the watermelon falls and lands atop of Akane's snorkel, causing her to fall out of her Swim ring and go under. Akane shouts she's downing, so Ranma goes to save her, but quickly realises the water is very shallow so tells Akane she can stand up now. Nabiki sarcastically retorts by saying they may be too late, while looking at the facedown Akane.

As Ranma picks up the unconscious Akane, a celebratory balloon appears saying "drowner number 10,000", to the confusion of Ranma and Nabiki. A group of men then run towards the trio, congratulating them for an excellent drowning. Ranma tells Akane she's so lucky, to which Akane angrily tells how it was soooo not fun. One of the men then explains that there's one more prize and presents a sparkling swimsuit which allows the wearer to swim freely.

Ranma watches the men whisper amongst themselves and thinks that something isn't right. Nabiki agrees with Ranma, she then goes over to the men and demands to know why Akane didn't win any money. Ranma looks on annoyed and says that's not what she meant, continuing Ranma says that there's no such thing as a swimsuit which makes a person able to swim and there is no one in the world dumb enough to believe otherwise.

Akane Tries the Swimsuit
Unfortunately for Ranma, Akane believes the men and tries the swimsuit on. Excited about trying out the swimsuit, Akane jumps into some deep water. After some times passes Nabiki and Ranma believe that Akane must've drowned so Ranma jumps in to save her.

However, when Ranma looks for Akane she can't see her until Akane (who sneaked up behind Ranma) pokes Ranma's back, scaring Ranma greatly. Angered, Ranma asks Akane what she thinks she's doing, to which Akane replies she's swimming. This annoys Ranma more, who tries to swim after Akane, but Akane tells Ranma to catch her and manages to swim at a speed that even Ranma can't keep up with.

Akane then thanks the God of the Sea, to which the imaginary God of the Sea replies that she shouldn't mention it since she's so cute and such a nice girl. Ranma, however, shouts at Akane asking her what crazy thing she's dreamt up now.

Back on land one of the men from the group earlier tell Akane that there's a long distance swim tournament and hands her a flyer. Akane walks off while the men tell her not to forget to sign up, to which Akane thanks the men.

That Night
As the sun sets, Akane hangs her new swimsuit up so it can dry at the inn they are saying at. Ranma (in his male form) waits for Akane to leave, so he can unhook the swimsuit and inspect what it is that allows Akane to swim. Just then the swimsuit moves, much to Ranma's shock, however, it turns out to just be Happosai trying to steal it. When Happosai says he saw it first, Ranma sends him flying saying that he's not like that. Akane then hits Ranma with a mallet, commenting on how he's just like the perverted old freak.

Next Morning
An announcement is made telling all the participants of the long distance swim tournament to gather at the appointed place. When Ranma (back in his female form) and Akane arrive they see a lot of other girls wearing the same swimsuit as Akane. Ranma also notices that they all have short hair just like Akane's, making Ranma very suspicious.

The man who gave Akane the flyer starts the race, while also explaining that the first to the rock in the distance wins. The girls with the swimsuits leave with tremendous speed, with Akane out in front. Shocked by the speed, Ranma just stares in awe, until a boat with the men in it appears telling her that she can't compete without the official suit on. As Ranma wonders what they mean, she's attacked by a hugh whirlpool and tidal wave, which makes Ranma land, head first, on a large rock.

Angered, Ranma jumps atop the man who gave Akane the flyer and grabs the scruff of his shirt. Ranma then states that this isn't any normal long distance swim is it.

Back to the Race
The other competitors are nearly at the island, when some realise that it was further than they thought. Tired the two of them decide to go back, when some jellyfish appear, which terrifies the two so that they continue to swim.

Meanwhile, Akane has nearly reached the island and is about to cross what appears to be the finishing line. Suddenly the finishing line wraps around Akane and lifts her into the air. Ranma then arrives and sees the "finishing line" is actually a tentacle of a large creature. Ranma asks what it is, to which the man in the boat says that it's the Protector of the Sea, the Great King Jellyfish.

The priest who gave Akane the swimsuit then explains that once a year they must offer up a maiden or face a deadly curse. Ranma believes that they are offering Akane as a sacrifice and goes to save her. However, just as she is about to kick the Great King Jellyfish, it presents her with a flag with a number "2" while also giving Akane a flag with a "1" on it.

After the Race Finishes
The Great King Jellyfish then presents Akane with a trophy and the two have a picture together. Annoyed, Ranma asks how this is a sacrifice, to which the man who gave Akane the flyer asks Ranma what she means by "sacrifice". Ranma then shouts at the man saying that didn't he say they needed to present a young maiden to him. The flyer man says that they have, while the priest explains that they meant a young maiden to hold. The Great King Jellyfish then begins to throw Akane into the air and catch her. While another man says that it really loves to offer up maidens, Ranma angrily says that "toss up" is more like it.

Later on, Akane is unhappy that her swimsuit has dried out, to which Nabiki (who's getting a suntan on her back) says what does she expect since it was a Jellyfish swimsuit. Ranma (back in his male form) is eating some corn with Genma, while the two men try to convince him to wear some Jellyfish swim trunks as they need a young man or the Great Queen Jellyfish will cast a curse on them, but Ranma isn't having any of it and tells them to shut up.

Cast in Order of Appearance

 * Akane Tendo
 * Nabiki Tendo
 * Ranma Saotome (female)
 * Happosai
 * Ranma Saotome (male)
 * Great King Jellyfish (debut)
 * Genma Saotome (panda)

Trivia

 * This is the first and only time Akane swims well.