On the way to Celestic Town, Ash and his friends are camped at a mountain cabin. While Dawn trains and Ash snoozes, Brock goes down the mountain to visit a pharmacy. That leaves Ash and Dawn in charge of the Pokémon, and their first task is to give the Pokémon a shower. Ash accidentally blasts Pachirisu with cold water, but everything seems to go smoothly. After that, it's lunchtime and a siesta! But naptime is cut short when Pachirisu comes down with a bad fever and there's no Pokémon Center in the area.
While Staravia goes out to find Brock, Ash has Buneary use Ice Beam to make an ice pack for Pachirisu's fever. The little Pokémon is still unwell, and Dawn and Ash argue over whose fault it was before they realize they need to find the berries that Brock uses for sick Pokémon. Meanwhile, Team Rocket sees a Zapdos fly by and try to hit it with a cannon full of sticky goo, but they hit Staravia instead. It manages to evade them, but now it can't fly. When Staravia fails to return, Ash sends Gliscor out to get Brock instead.
Alerted by Gliscor, Brock runs back to the cabin and realizes that Pachirisu may have a build-up of excess electricity. Once he drains the extra charge and treats Pachirisu with medicine and Oran Berries, it's on its way to a speedy recovery—just in time to be stolen by Team Rocket, who spotted the cabin! But Staravia found some friendly Wooper to clean the gunk off its wing, and it returns in time to free Pachirisu from Team Rocket's net. Then Buneary and a healthy Pachirisu team up to blast Team Rocket back where they came from. It looks like a happy ending all around, except that they forgot about one Pokémon: poor Gliscor, still struggling up the long road back to the cabin!