S5·E41 The Ice Cave!

Episode recap

Ash, Pikachu, Misty, Brock and the rest of the traveling group decide to take an ice‑filled cavern that serves as a shortcut toward Blackthorn City. The passage is described as an icy tunnel that the party must navigate in order to shorten their journey. Early in the episode the group encounters Team Rocket in a watery situation, a brief clash that interrupts their progress through the frozen corridor. During the ensuing events Brock becomes ill, catching a cold as a result of the frigid environment inside the cave.

While the group continues forward they discover an unexpected facility built into the interior of the cavern: a Pokémon Center. Inside the center a Jynx is shown attending to Brock, providing care for his cold. The presence of the Jynx indicates that the center is staffed and operational despite the remote, icy location. Nurse Joy, who is also present at the center, explains to Ash and Misty that the persistent cold within the cave is caused by a large structure that functions as a refrigerator. The refrigeration system is identified as the source of the low temperature that makes travel through the tunnel difficult.

Team Rocket, having followed the group, locates the refrigeration building. Their plan involves manipulating the structure; they reverse its operation, which has the effect of heating the interior of the ice cave while simultaneously causing the temperature outside the cave, in the surrounding jungle, to drop. This reversal creates a dramatic shift in the environment, turning the once‑cold tunnel into a warmer space and chilling the external area. In addition to the environmental sabotage, Team Rocket attempts to capture the Ice‑type Pokémon that inhabit the cave, seeking to add them to their collection.

The episode therefore intertwines the characters’ quest for a shortcut with the discovery of a hidden Pokémon Center, the medical assistance provided by a Jynx, an explanation of the cave’s artificial chill, and Team Rocket’s interference that both alters the temperature balance and threatens the Ice‑type residents. The narrative resolves with the group confronting the reversed refrigeration system and dealing with Team Rocket’s attempt to steal the cave’s Pokémon, while also addressing Brock’s cold condition.