Ryugujo Arc is the 18th arc in Gintama.
Yorozuya went to the beach with the mission to catch a suspicious person, however, they started to look at chicks with their binoculars. Kagura caught Kamenashi videotaping girls in their swimsuit and proceeded to beat him up. They agreed on not to take Kamenashi to the police as he would take them to Ryugu Palace.
In the sea, they saw a cruiser and Kyubei, Otae and a golden turtle was on board. They have saved his daughter from some punks, so he was taking them to Ryugu Palace. Later, they saw a warship and Hasegawa was on board with a badass turtle. The turtle had saved Hasegawa when he was about to jump of a cliffand was taking him to Ryugu Palace. Suddenly, Katsura appeared, riding a flying soft-shelled turtle, and was going to Tianzhu. These two turtles started to fight and everyone got lost in the sea as their boats got destroyed.
Shinpachi woke up on the shore and saw a skeleton in a cave nearby. He thinked about things such as getting old in the island, but later started to think positively and stripped naked. He started to run and thought that he isn’t alone as he is a part of the world. He really wasn’t alone. Hasegawa was doing the same thing as him. They put on their clothes and started to speak like nothing happened. They found Gintoki practicing Kamehameha and when he saw them, he got embarrassed. They pretended like they saw nothing. Then, they saw Otae singing B’z’s Taiyo no Komachi Angel, and she got emberassed when she saw them. They tried to make her feel better and found Kyubei on their way. She drew an ice cream, but the waves erased half of it and made it look like poop, and she used her body as a wall to protect it from the waves. After she saw them, she got emberassed and Otae tried make her feel better. They found Kagura, stating that Laputa must definitely be on that huge cloud. She also felt very bad when she saw them and Otae tried to make her feel better with Kyubei. At last, they saw Katsura. He was drawing an SOS with his piss and was singing Taiyo no Komachi Angel. He saw a giant cloud and stated that Takizawa Crystal must be there and ran out of piss. He also protected the SOS from the waves with his body, making Gintoki and Shinpachi furious. They talked about their situation and made three groups. Hasegawa and Otae were in charge of cooking, Kyubei and Shinpachi were in charge of finding shelter and Katsura, Kagura and Gintoki were in charge of exploring the island.
Hasegawa caught lots of fishes Otae burned his sunglasses to start a fire. Katsura and his group found a giant box in the forest. Katsura accidentally touched the box and a gas came out of it, turning Gintoki and Katsura into old men.
The turtles put them into a prison and reported this to Otohime. She ordered Kamenashi to be executed and the others to get old. Matsudaira was also in the Ryugu Palace, having fun with women and drinking Don Perigon. They called him from Edo and reported that everyone turned into elderly chumps and he didn’t believe it.
In the prison, they started to talk about their strategies and Gintoki was watching sumo watches with Katsura. Kagura thought Gintoki was eating something and attacked him. Katsura got disturbed by the noise and stated that kids must stop playing with the mega drive and go outside. They all got annoyed by Katsura and Gintoki’s behaviours and some turtles appeared. They took Otae and left. Then Kamenashi came and pushed the guard to the bars to make them take the keys, but Kagura kicked the bars down. The turtles attacked them but Kyubei and Kagura defeated them.
They went into the palace and Kamenashi told them to act like turtles, resulting in all of them doing stupid things and making Shinpachi crazy. Kamenashi told everyone that Otohime is doing this to make everyone look ugly, so she can be the most beautiful creature.
The turtles took Otae to Otohime and she stated that Otae isn’t beautiful at all, making her go crazy and provoke Otohime to show her face.
Before they went to take Otae back, Kamenashi used spouzer to divide their power equally, but the spouzer got destroyed as Gintoki and Katsura were too much of a burden. The soldiers found them and started to attack. Kagura and Kyubei fastly escaped as they didn’t want to be team up with Katsura or Gintoki. Kamenashi and Hasegawa tried to hold the turtles so Shinpachi and others can escape, however, they couldn’t even stop one soldier and fell down. Shinpachi carried Gintoki and Katsura, and tried to escape from the soldiers.
Because Otae insulted her, Otohime wanted to execute Otae. When Otae said to Otohime that she was ugly and didn't know what real beauty was moments before her execution, Otohime dropped her in a pool full of sharks.
After getting away from the soldiers, Shinpachi, Katsura and Gintoki entered into a room and there was a man in a capsule. Katsura sit on the controller and the computer opened, showing Otohime’s journal, mostly about Urashima.
Kyuubei and Kagura then came to save Tae and freed her from the rope, they teamed up to beat up the sharks as well as Otohime's subordinates. After that, Tae beat up the last guards protecting Otohime and finally continued beating Otohime up until she stopped her project. Their fight was interrupted by more subordinates surrounding Tae with their guns, buying Otohime enough time to let the poison spread inside her palace, letting everyone, including her own subordinates, age extremely fast.
After reading the journal, Gintoki asked Zura if he can run straight, and went to ‘’rehabilitate a 3000 year old woman’’. Urashima communicated with Shinpachi through the computer and told him about the antidote.
Gintoki and Katsura went to stop the cannon, and old turtles confronted them. However, as all of them are old, Gintoki stated that there isn’t any way that they will lose and started to run much faster than the others. Shinpachi catched up to them with the antidote on his shoulder. But, their new challenge was stairs, and it was very hard for Katsura and Gintoki. However, Hasegawa, Kamenashi, Kyubei, and Kagura tried to stop Otohime and earned them some time. Before they put the antidote into the cannon, Otohime caught the antidote and made it fall down. But, the antidote leaked, resulting in Katsura and Gintoki return to their former selves and they easily shot the antidote into the cannon. Everyone in Edo got back to their old selves. Otohime lost and got stuck under the parts of the cannon that was destroyed, but Gintoki and others saved her.
The Ryugu Palce got destroyed and Otohime opened a snack house. Hijikata and Kondo become its regular costumers and Otohime gave advices to Kondo whenever he got dumped by a woman. Then a person who resembles Urashima appears in the shop.
Characters in order of appearance
- Sakata Gintoki
- Shimura Shinpachi
- Shimura Tae
- Yagyuu Kyuubei
- Hasegawa Taizou
- Katsura Kotarou
- Hanano Saki
- Otohime (debut)
- Matsudaira Katakuriko
- Kondou Isao (cameo)
- Hijikata Toushirou (cameo)