This article is about an episode of the Pokémon animated series that has not been dubbed into English. As such, its coverage may contain romanized Japanese names, rather than dub names.
Spoiler warning: this article may contain major plot or ending details.
Plot
In the dead of night, Skeledirge and Lycanroc sneak into the Brave Olivine's cargo hold to have a midnight snack on Berries. They suddenly freeze, though, when someone who looks like Captain Pikachu enters the room, but when it starts laughing, it transforms back into its true form as a Ditto. The two Pokémon quickly befriend it, and come next day, while the crew is having a clean-up day by feeding their unnecessary items to AlolanMuk, they introduce Ditto to Meowscarada, Quaquaval, and Sableye. Quaquaval and Sableye instantly befriend it, while Meowscarada remains wary of it, choosing to hide behind Quaquaval. Ult brings in a huge rock that he found and wants to add to his collection, but Roy and the others remind him that they're cleaning up the ship and tell him to take it back. Murdock notes that the ship is getting a bit cramped, and that they don't have much more space onboard. Overhearing this, the Pokémon start worrying that Ditto will not be allowed to stay if the crew finds it, so when Liko comes to ask for Meowscarada's help in cleaning up her room, Quaquaval hastily hides Ditto out of sight. Meowscarada follows Liko to her room, but Skeledirge, Quaquaval, and Lycanroc realize that Ditto had disappeared and frantically start searching for it, unaware that it has tagged along with Meowscarada by transforming into her tail.
In Liko's room, she starts sorting her personal items into boxes based on whether she wants to keep them or throw them away, specifically making sure that a wooden Squawkabilly carving goes amongst the kept items. In the middle of the cleaning, Meowscarada suddenly notices Ditto on her tail and starts frantically trying to pull it off, freaking Liko out as Meowscarada's "tail" seems to stretch unnaturally long. The other Pokémon quickly rush in to keep Liko from seeing Ditto just as Meowscarada manages to pull Ditto off, though not without sending a lot of items flying around in the process. Quaquaval quickly hides Ditto in Skeledirge's mouth and runs out with him, Sableye, and Lycanroc as the sudden situation calms down. Liko calms down as well as she and Meowscarada regather the scattered items, though Meowscarada fails to notice that she accidentally places the Squawkabilly carving into the box of disposable items. They head outside, where Ditto once again causes confusion by transforming into an extra member of Mollie's MausholdFamily of Four, which the Pokémon quickly catch and carry away, Roy mistaking their activity as them playing while Meowscarada places the contents of her box, including the carving, inside Muk's mouth.
Hiding in the ship's bridge, the Pokémon are amused seeing Ditto briefly transforming into Nosepass's nose and go on to introduce it to the rest of the ship's Pokémon and amuse them with its transformations, though they are quick to again hide Ditto as soon as the crew heads past them for lunch. In the dining hall, while everyone else sits down with their usual meals, Murdock points out that he's been having Lycanroc taste test some of his treats again, which has caused it to become chubby once more, so he's putting it on a Tamato Berry diet, much to Lycanroc's dismay. To help Lycanroc, Ditto secretly transforms into a part of its muzzle to eat the Berries in its stead. At first, Murdock is happy to see Lycanroc eating, but feeling its "muzzle", he notices how oddly squishy it feels. The Pokémon in the room start to panic and begin causing random chaos to create a distraction while Ditto hides by transforming into Noctowl's eyebrow. While the chaos still ensues in the background, Liko comes in and asks Meowscarada if she's seen her Squawkabilly carving, being sure she placed it amongst the items she wanted to preserve, causing her to freeze in horror upon remembering that she accidentally fed it to Muk and that she accidentally thrown away something that's precious to her Trainer. Oblivious to Meowscarada's terror, Liko figures that Meowscarada doesn't know what she's referring to, and leaves to look for it again.
Meowscarada, Skeledirge, and Quaquaval celebrating Ditto joining the crew
Later, Ditto finds Meowscarada crying in sadness over what she's done. Feeling sympathetic for her, Ditto decides to help by transforming into a copy of the carving, which Meowscarada takes to Liko to pretend that she's found the lost precious item. In return, Liko shows Meowscarada a foxtail toy that they used to play with long ago, almost unknowingly tickling Ditto into exposing itself until Meowscarada hastily plays with the toy for a while before running outside, where the other Pokémon have gathered around an unnerved Muk. Some of them decide to try diving into Muk's mouth to retrieve the carving, but Snorunt gets scared and Pawmi trips and hurts itself before it can do so, so Meowscarada takes it upon herself to fix her mistake. After her pleas to Muk fail to get the item back, she's prepared to jump into its mouth herself, only for Liko to show up and start holding her back, not understanding what she's trying to do. As the unusual situation is being observed by Roy and Dot, Ditto suddenly shows up and returns to its usual form, finally revealing itself to the children, before transforming into a copy of Meowscarada's foxtail toy, allowing Meowscarada to use Ditto to tickle Muk into sneezing, causing it to spit out all the items it has eaten that day, including Liko's Squawkabilly carving, which Ditto retrieves and returns to its rightful owner.
While Roy checks Ditto on his Pokédex, Ult excitedly approaches it, having never seen a Ditto before. The other Pokémon rush in to defensively protect Ditto, who solemnly starts to leave upon assuming that the humans will kick it out, but Liko stops it, as she and her friends understand that it clearly feels at home aboard the Brave Olivine, and the Pokemon aboard clearly enjoy its company. As such, with one final approval from Captain Pikachu, Ditto officially joins the Rising Volt Tacklers, much to its happiness as the Pokemon celebrate. That evening, Liko explains to her friends that her carving is so precious to her because it was a gift from her grandmother. As everyone goes to sleep, the narrator explains how Ditto's habit of transforming into a rock while sleeping has caused Meowscarada and Sableye to fight over which of them gets to sleep with it, with Meowscarada taking it from the sleeping Sableye's grip to sleep with her instead.
