Spring Fever (Japanese: ここほれウリムー！おんせんをさがせ！！ Dig Here Swinub! The Search for the Hot Spring!!) is the 31st episode of Pokémon: Johto League Champions.
With their old pal Todd Snap back with them, Ash and company decide to postpone going to Olivine City and help him get a picture of Articuno. During the trip, a Swinub appears and chows down on Misty's Rice Cake (Uh-oh). After following it, they find out it was one of three belonging to a man named Rory and his daughter Peggy, both of which are water prospectors. This gives Meowth an idea: Use the Swinub, have them locate hot springs and open a spa service. Will this latest plan succeed? And where is Articuno going now?
The heroes have a sight on the mountain, where they hope to see an Articuno. Soon, they have lunch, as they eat Brock's rice balls. Misty goes to give Togepi a drink, but her rice ball gets eaten by a bunch of Swinub. Ash sees they like eating more than he does. A girl comes to stop Swinub from eating the rice balls. She scolds them, but Brock assures her they got plenty more to eat. Nevertheless, she scolds her Su, Ein and Ub, while the girl introduces herself as Peggy. The heroes ask if these Swinub are hers', but she shakes her head and leads them to her father. She tells he is a professional hot spring digger. The man clarifies that he needs to find the hot springs for others to build hotels and resorts around them. However, even with experience, he cannot find them.
The man assures Peggy he will find them, using the Swinub to detect the hot springs, since they can sniff out underground steam. The Swinub detect something, so the man sends Graveler to dig out. James and Meowth observe that, while Jessie is overjoyed, since she loves hot springs and sauna. James and Meowth are not amused by this, as they need to steal Pokémon. Jessie refuses and thinks they should concentrate on building spa centers, wanting to name them as "Jessie's lodge". She is forced to change it to "Jessie and James and friend's lodge", since James and Meowth object. She goes to find the hot springs, leaving Meowth and James to be surprised Wobbuffet appeared. The heroes see Swinub failed to search for a hot spring. Peggy worries, since they have run out of supplies and have not found a single hot spring. The man, Rory, is still happy, as he feeds Pikachu and Swinub. Jessie and James come, disguised as workers, telling Rory they came on behalf of the resort company to help him dig (though Jessie shushes James, as he almost told they were experts on traps).
The Swinub detect a hot spring, so Rory sends Graveler, who digs out. Jessie and James see Graveler digging, though Jessie tells James not to mention traps. The heroes and Team Rocket dig, but James sees there are no hot springs around. Jessie plans on stealing Graveler and Swinub, then force them to search. She asks Rory to borrow Swinub and Graveler and he permits her to do as such. Jessie comes with Graveler and attempts to steal it, but is too heavy. Still, James steals the Swinub and tells Meowth to commence the plan. Piggy searches for Swinub and sees James stealing them, so warns the heroes and Rory. Jessie and James reveal themselves and go in Meowth's vehicle away. Ash, Rory and Brock go to stop them, but fall in a hole. Still, they use boxes to track them. Meowth sprays oil to deter them, but the heroes still follow them, evading the oil. Team Rocket goes in a tunnel and when they are on the other side, Meowth drops the oil he intended for cooking, cleansing and lusting dull furniture. James still hopes he did not buy it from the food money.
The heroes come through the tunnel, but get stopped, since they ride boxes on the slippery oil. Team Rocket depart away. Todd sees Articuno and goes to take a photo of it, but falls out of the box before doing it. The heroes saw it, but promise to return Swinub back before going to the mountain. Later, Jessie thinks Swinub should search for the hot spring before they are given to the boss. She lets the Swinub search and soon, James and Meowth dig out, but know Graveler could have dug out instead. Suddenly, they hit a liquid, causing Jessie and Meowth to be happy, since it is a hot spring. James checks and it is oil, disappointing Jessie and Meowth. Suddenly, Jessie and Meowth realize they are stinky rich. James disappoints them, as he believes they hit a pipeline. After realizing they could end up in jail for this act, Team Rocket runs away, while Noctowl observes. Noctowl comes back and reports to its master.
Soon, the heroes find Team Rocket, who demand Swinub back. Jessie replies she will be keeping Swinub to find hot springs, then give it to the boss. Ash sends Totodile, Misty Poliwhirl and Rory Graveler. Jessie sends Arbok and James Victreebel, the latter chewing James. Arbok uses Headbutt, but gets scratched by Totodile, with Graveler tackling it. Victreebel uses Razor Leaf, though Graveler takes less damage via Defense Curl. Poliwhirl uses Double Slap, hitting Victreebel. Rory goes to free Swinub, but Meowth stands in his way. Graveler tackles Meowth, so Rory frees Swinub. James sends Weezing, so Jessie tells they have the whole line, but remembers she forgot Wobbuffet, who came out. Swinub begin to hiss, as they are angry for being stolen. Su goes to battle Arbok, but gets wrapped. Ein uses Take Down and dodges with Su from being bitten. Ub uses Tackle, though gets countered by Wobbuffet. Todd takes pictures of the battle, but leaves once Jessie poses to be photoed. Jessie sees kids these days have to talent and presents a magazine where she was photographed, but appears far distant in it.
Victreebel and Arbok fainted. Weezing uses Smokescreen, but gets cleared out by Poliwhirl's Bubble. The Swinub use Powder Snow, freezing Team Rocket's Pokémon. By tackling, Swinub shatter the ice, while using Water Gun Poliwhirl and Totodile blast Team Rocket off. Rory sees even if they cannot find the hot springs, Swinub are still touch fighters. Suddenly, the Swinub act very energetic around a spot, so Graveler digs. Soon, water emerges, so Rory sees his work paid off finding a hot spring. Brock thinks the battle got the Swinub warmed up. The heroes wave goodbye to Piggy and Rory, as they go to find Articuno.
- This is the first of many episodes where "To Be Continued..." actually appeared onscreen. This wasn't the only change to happen however.
- The "Who's that Pokémon?" is Farfetch'd.