Misty has a problem: her Psyduck can't swim. It doesn't even like water! So when Tracey stops by the Cerulean Gym for a visit, the two Trainers give Psyduck some swimming lessons, with absolutely no success. Then Sakura, a familiar face from Ecruteak City, stops by the Gym to challenge her friend Misty and earn the Cascade Badge. That's when Misty gets a big surprise: the Gym ran out of badges and her sisters forgot to tell her! The Cascade Badges are made by an artisan in Rifure Village, so Misty, Tracey and Sakura head out to find him. Near the village, they rescue an injured man who turns out to be Kinso, the very man they need.
Even with an injured ankle, Kinso is a tough old man. He won't just hand over the badges: he wants everyone to work for them. That means waking up at 4 AM to run laps, split wood and craft their own badges. If they don't do it right, they'll have to wake up the next morning and do it all over again! It takes two days to get the hang of it and there's still one more test: a battle with Kinso's Feraligatr. Misty accepts, but her Psyduck breaks out of its Poké Ball and falls into a pond. When Kinso sees that, he refuses to give the Cascade Badges to someone whose Water Pokémon can't even swim!
When everyone returns to the cabin, they discover that the thieves have stolen all the badges. Our heroes confront the two badge thieves who refuse to give up. Instead, they send out their Poochyena and Zigzagoon to fight. But when Poochyena bites Psyduck on the head, it triggers Psyduck's real power and it uses Confusion to stun the thieves. This proves to Kinso that Misty is worthy of the badges after all, so now it's back to the Gym for Misty's battle with Sakura. Sakura's Espeon not only swims, it knocks Misty's Corsola out with Psybeam. At last, Sakura has earned her own Cascade Badge!