When Ash’s Hawlucha finds a Pokémon Egg, everyone teams up to keep it warm, including a very helpful Fletchinder. Soon, a cute little Noibat hatches from the Egg! It starts trying to fly at once, but isn’t very successful. Hawlucha tries to show it how to ride the wind—until Team Rocket swoops in and grabs both of them!
Jessie and Meowth are hoping to evolve Noibat on the spot into a powerful Noivern, but James does some research and learns it won’t be that easy. During their discussion, the two Pokémon manage to escape into a pitch-black cave, where they quickly get the better of the villains thanks to Noibat’s sonar.
Once everyone is reunited and Team Rocket is sent blasting off again, our heroes are ready to set off again toward Anistar City—and Noibat decides to join them!
While on their way to Dendemille Town and Anistar City, Ash and his friends take a short rest. While everyone is relaxing, Hawlucha is in the nearby forest practicing its moves against an old tree. After knocking off one of the tree's decaying branches, Hawlucha sees something glowing at the base of the tree. As everyone is preparing to leave, they notice Hawlucha's absence as Hawlucha arrives, carrying its discovery. Ash and Clemont both immediately recognize the object as a Pokémon Egg, and Hawlucha takes them back to the place where it first saw the Egg. Suddenly, the Egg begins to glow and they all realize that it is about to hatch. Per Serena's suggestion, Ash begins to try and warm the Egg by wrapping his body around it, and all of his Pokémon help as well. Fletchinder uses its Ability, Flame Body, to speed up the Egg's hatching.
Finally, the Egg hatches to reveal a baby Noibat. As Noibat opens its eyes, it sees Ash and the rest of the group as they all introduce themselves to it. However, the Noibat is overwhelmed by all of the attention and uses Supersonic. Bonnie tries to calm Noibat down, but it continues using Supersonic and Ash is the only one able to comfort it. Once Noibat has stopped crying, everyone looks for fruit that Noibat likes to eat. Unfortunately, when Dedenne picks a fruit for Noibat, Noibat uses its highly sensitive ears to examine the fruit and refuses to eat it. Trying to convince Noibat to eat the fruit, Bonnie takes a bite and discovers that it tastes terrible. All of the Pokémon help to pick lots of fruit for Noibat to examine, but it deems them all inedible. Noibat then discovers that Bonnie is holding two more pieces of fruit, and it decides that they will taste good.
Once Noibat has finished eating, it walks away and tries to fly into the air, but it soon falls back to the ground again. When Ash comforts Noibat again, Serena surmises that it might consider Ash to be its parent. Although Noibat's second attempt at flight is again unsuccessful, Ash manages to catch Noibat before it falls to the ground again. Team Rocket, watching from a nearby tree, decide to steal Noibat because its evolved form, Noivern, would make a good addition to Team Rocket's ranks. Meanwhile, Fletchinder and Hawlucha assume the roles of Noibat's teachers, guiding it through the air and showing it how to fly. Although Noibat does much better this time, it still fails to remain airborne for more than a few seconds. At this, Clemont suggests teaching Noibat to glide before teaching it how to fly, and Ash tells Hawlucha to instruct Noibat. Once again, Noibat does very well, but only for a moment. Fortunately, Hawlucha catches it before it can hit the ground again. At this, everyone is out of ideas for how to teach Noibat to fly, when Hawlucha suddenly remembers something and leads the group to a hill with a strong breeze at the top. Hawlucha flies out into the air, followed by Noibat and Fletchinder, when suddenly a huge net comes out of nowhere and ensnares Hawlucha and Noibat. Team Rocket reveal themselves and then leave, with Ash's Pokémon in tow. Despite Fletchinder's attempts to stop them, Inkay keeps it at bay long enough for Team Rocket to escape.
Once Fletchinder has recovered from Inkay's attack, it immediately goes off in search of Team Rocket. Meanwhile, Hawlucha and Noibat have been tethered to a tree, and Noibat's Supersonic does nothing against the special earplugs worn by Jessie, James, and Meowth. Hawlucha and Noibat both try to escape, but without success. While Jessie, James, and Meowth are trying to figure out how to evolve Noibat, Hawlucha surreptitiously picks at its rope with a sharp claw and tears through it. Hawlucha does the same to Noibat's tether, but just as the two of them are about to escape, Jessie spots them and Inkay and Pumpkaboo give chase. Because Noibat is still unable to fly, Hawlucha carries it on its back. Inkay and Pumpkaboo are no match for Hawlucha's superior agility, and Hawlucha hides with Noibat in a nearby cave. As Fletchinder watches from overhead, Jessie, James, and Meowth head into the cave, leaving their Pokémon with instructions to attack Hawlucha and Noibat as soon as they exit the cave.
Unfortunately for Team Rocket, the cave is pitch black. Using echolocation, Noibat tells Hawlucha exactly where each member of Team Rocket is, and Hawlucha brings them down one by one, knocking off their Supersonic-resistant earplugs. Noibat then uses Supersonic again, driving Team Rocket out of the cave and into Inkay and Pumpkaboo's waiting ambush. At that moment, Ash and his friends arrive, and Frogadier easily defeats both Inkay and Pumpkaboo. After Pikachu sends Team Rocket blasting off, Hawlucha and Noibat emerge from the cave. That evening, Ash invites Noibat to continue traveling with him, and Noibat happily agrees.