Misty has returned to Cerulean City to step in as the Cerulean Gym Leader. But as soon as she arrives, she hears a news report about the Pokémon Investigation Agency closing Gyms that fail to meet proper standards—and rumor says Cerulean City is their next stop! Unaware that three of her enemies are in town, Misty rushes to the Gym and finds an out-of-control Gyarados in the pool. Neither Nurse Joy nor her sister's fan club can control it, and she can't just stick it in its Poké Ball while it's still upset. It's Misty's duty as Gym Leader to solve the problem, except she's also had a Gyarados phobia ever since she was a baby!

Misty puts on a water show costume and swims in the pool, hoping to stir Gyarados's memories of performing together back when it was a Magikarp. Instead, Gyarados turns the pool into a raging whirlpool, and Misty blacks out. As her Horsea rescues her, she dreams of Ash and Brock telling her she can do this on her own.