In their secret base, Team Rocket is dismayed to find Morpeko having eaten all of their food yet again, even breaking into a safe to get the snacks James had hidden in it. Meowth suggests they should catch it to make it obey them, but Jessie rejects the idea and instead declares that they'll release it back into the wild.
James is chosen to carry out this task, but as he and Morpeko are walking away from the city together, he starts feeling uncomfortable with the idea, especially when Full Belly Mode Morpeko actually shares some of its delicious seeds with him. He tries to lose it, but Morpeko keeps following him. Eventually, they wind up back in Vermilion City, where Morpeko finally runs out of seeds and turns into its Hangry Mode as a result. James quickly rushes to a nearby food stall and buys everything they have. While Morpeko is eating, James runs away, and by the time Morpeko finishes the food and changes back into its Full Belly Mode, James is long gone. However, Morpeko had unintentionally left behind a trail of seeds, which it finds and follows back to Team Rocket's secret base. When the trio returns there with bagfuls of food, they're shocked to see Morpeko in its Hangry Mode, who swipes the bags from them before using Aura Wheel to send them blasting off.
The next day, while Team Rocket is out on a shopping trip for more food, with Morpeko right behind them, they notice Ash and Goh nearby. Seeing Goh catching himself a Raticate, the trio gets the idea of having Goh catch Morpeko to stop it from troubling them anymore. They try various tactics to make this happen, like placing Morpeko right in the twerps' path or having Jessie disguise herself as a fortune teller to point them towards it, but each plan fails for one reason or another. While the trio laments their failures at a park, Morpeko notices a Pokémon food delivery van nearby and sneaks into it. James tries to tell the car to stop, but Jessie says that this method works too and simply waves after the car. Inside the van, Morpeko has eaten its fill and falls asleep, falling into one of the delivery boxes as the car drives along.
The box containing Morpeko winds up at the Cerise Laboratory, with Ash and Goh discovering it when they prepare to feed their Pokémon. Almost as soon as Morpeko wakes up, it turns into its Hangry Mode and starts devouring food from the boxes. Goh's Greedent also starts doing the same, and the two gluttonous Pokémon begin a fierce competition for food, with Morpeko even trying to rob food from Greedent's stash. The situation is resolved when Goh's Raichu starts bringing copious amounts of Berries for both of them to eat. Goh tries to catch Morpeko while it's distracted, but it immediately pops out of the Poké Ball and resumes eating without missing a beat. Goh is dismayed at having lost to Morpeko's appetite, but Ash tells him he could try catching it again later once it's calmed down. Meanwhile, Team Rocket is planning their next heist, intending to steal lots of Pokémon at the local shopping mall, but James keeps getting distracted by his worry about Morpeko's condition.
The next day, Ash and Goh head out again, not noticing Full Belly Mode Morpeko following them. When they come close to the shopping mall, they hear commotion and head inside to find Team Rocket using a big vacuum to steal loads of Pokémon. The trio boasts that they've eaten their fill for the first time in ages and are feeling great. While Ash and Goh prepare to confront the trio, Morpeko notices the cart of food the trio has bought. Jessie and James call down the Rocket Prize Master, but the Pokémon they get, a Natu and a Zigzagoon, seem underwhelming to them. During the ensuing battle, Natu gets hit by Cinderace's Pyro Ball and is sent flying into Morpeko, who had just been about to dig into the contents of the food cart. As Team Rocket notices Morpeko, it turns into its Hangry Mode, and, enraged by its meal being interrupted, uses Stomping Tantrum, which deals super effective damage on both Pikachu and Cinderace. Jessie is delighted to see such power on their side, but unfortunately, Morpeko next uses Aura Wheel on the trio and sends them blasting off again. The stolen Pokémon are freed, and Morpeko empties the food cart before walking away. Ash and Goh are left confused by what just happened, but their attention is quickly redirected elsewhere when they spot a Pidgeotto. Goh quickly throws a Poké Ball at it, finally catching the Pokémon that's been eluding him for a while now.
Team Rocket has landed on a tree, hanging upside down from it, until they spot Morpeko nearby, calling out to them. Jessie and Meowth quickly hide and decide to let it pass by, but James, seeing how Morpeko came looking for them, climbs down and calls out to it. He then pulls out a Poké Ball and tosses it at the Two-Sided Pokémon, catching it. He immediately lets Morpeko back out and officially welcomes it to the team. As the trio prepares to head back, however, Morpeko's Hangry Mode is suddenly activated and it attacks the trio with Aura Wheel again, blasting them off once more.