Cassandra runs a medicine shop in Mossgreen Village alongside her grandmother. She's best known for her determination to get her Paras to evolve—she needed its evolved form, Parasect, specifically for the mushroom on its back to create a particular medicine. When Ash showed up, she asked him to battle her Paras to help trigger the evolution, but his Pikachu, Squirtle, and Charmeleon just ended up scaring the thing off instead.
Meowth, predictably, developed feelings for Cassandra pretty quickly. He managed to rope Jessie and James into helping by hyping up the fortune they could make off her miracle potion—he was also hoping to secure himself a nice home with her in the process. Through a combination of Team Rocket's meddling and sheer luck, Paras actually did evolve, and Cassandra got the Parasect mushroom she needed for her medicine.
Of course, Meowth's plan fell apart when Cassandra's grandmother discovered a Persian lounging in the backyard and decided to keep that instead.
Content compiled by AnimeList.moe from publicly available sources.
