Ash, Goh, and Chloe have traveled to Driftveil City, following a report about a new evolution of Klink. However, to the boys' dismay, the whole thing turns out to have been just a marketing trick for Klink-shaped cookies. Team Rocket, who had also followed the rumors to Driftveil, is feeling grumpy about having come all the way to Unova for nothing. However, upon spotting the twerps, they decide to use the opportunity to steal Pikachu.
As Ash, Goh, and Chloe sit down to eat the cookies they bought, they notice Grookey and Eevee examining a big hole on the ground nearby. The two Pokémon excitedly jump into the hole, prompting the three Trainers to follow. Team Rocket, seeing this, station Wobbuffet at the entrance with a net to capture Pikachu once it's chased out of the hole, before following after the twerps. In the cave below, Ash, Goh, and Chloe find Grookey and Eevee. Jessie calls for the Hyper-Capture Machine to be activated, but Meowth says Jessie broke it. Jessie angrily replies that Meowth should've fixed it. As the two argue, James accidentally drops Morpeko's Poké Ball, and the Two-Sided Pokémon emerges in its Hangry Mode. The commotion is more than enough to make Ash, Goh, and Chloe notice them, so the trio decides to resort to force instead. Jessie throws down a smoke bomb, which results in everyone blindly stumbling around. When the smoke clears, Ash is alone with Morpeko, Jessie and James find themselves having run away with Eevee instead of Pikachu, Goh is wandering around with Pikachu, Chloe discovers herself with Meowth, and Grookey is left wandering alone.
Each mishmash group interacts with their unexpected companions in different ways: Ash tries to handle Morpeko's near-constant hunger by reluctantly feeding it some of his Klink cookies; Goh tries to tell Pikachu to move around with more planning; Chloe questions why Meowth does evil things; Meowth starts falling in love with Chloe upon witnessing her kindness and caring towards him; Jessie and James decide to convert Eevee into a Team Rocket member to spy on the twerps; and Grookey discovers a tunnel leading back to the surface.
Goh and Pikachu notice an awful stench in the air and discover it's coming from a sewer that the tunnel is connected to. In the sewers, they're attacked by a Seismitoad. After Pikachu tries to battle it on his own, only to have his Thunderbolt fail to do anything due to Seismitoad being part Ground type, Goh instructs him to use Iron Tail instead. The attack hits, but before Goh can throw a Poké Ball to catch Seismitoad, Pikachu hits it with another Iron Tail, causing it to fall into the water and swim away. While Goh is dismayed, he realizes that Pikachu's way of taking the lead reminds him of Ash, showing that Pokémon indeed tend to take after their Trainers.
Chloe asks Meowth how he learned to talk, and he explains that he did it a long time ago to impress a girl he liked. Meowth tells Chloe that he likes kind girls, and she says that if he wants someone to be kind to him, he should be kind to them back. She even suggests that he should quit doing bad things and make up with his friends if he's had a disagreement with them. Chloe's words touch Meowth deeply, and he decides to leave Team Rocket and let himself be caught by her.
While Jessie and James try to teach Eevee their motto routine, with James having second thoughts about replacing Meowth, Grookey wanders back to the surface and ends up stealing Wobbuffet's net to play with it. Each underground group, meanwhile, ends up running into a swarm of Durant, the Pokémon who nest in the tunnels, and run away from them. On the surface, Grookey accidentally angers a group of Heatmor, which starts chasing after it and Wobbuffet. Everyone ends up reuniting underground, with Eevee reuniting with Chloe; Meowth, Morpeko, and Wobbuffet rejoining Jessie and James; and Grookey rejoining Goh. As the Durant and Heatmor start fighting, everyone uses this as a cover to escape from the tunnels. Upon getting out, Goh discovers that one of the Durant had followed them, and catches it after gaining its approval. Meowth attempts to confess his love for Chloe, but accidentally ends up facing Jessie during his confession, which Jessie takes as an apology. Morpeko, still in its Hangry Mode, glares at everyone. Unfortunately, Ash has dropped his bag of cookies, and before James can recall Morpeko, it uses Aura Wheel to send both groups blasting off.
At sunset, Ash, Goh, and Chloe walk through a street and consider the day a success, despite the roughness they experienced. Team Rocket, meanwhile, is hanging from a tree while Morpeko eats Berries below them, with Meowth still longing after Chloe.