Like all the other Pokémon Trainers of this movie, Neesha received an invitation to meet "the world's most powerful Pokémon Trainer in the world" at New Island. Because of a storm created by Mewtwo himself, Officer Jenny wouldn't let the Trainers present in the movie travel to said island so Neesha, along with other Trainers, used Pokémon to get to New Island. Neesha used her Dewgong to go to the island by crossing the sea. Neesha arrived on New Island alongside Corey and Fergus. When Ash and his friends arrived at the island, Neesha introduced herself and her Pokémon team including her Dewgong from earlier in the movie. When Mewtwo arrived, she watched the others attacking Mewtwo but they all failed. To battle against a cloned Blastoise, Neesha chose her Blastoise, nicknamed ShellShocker. She commanded ShellShocker to use Hydro Pump on its clone but the clone repels the attack and uses Rapid Spin to knock its real counterpart out, instantly defeating Neesha in the process. When Mewtwo tried capturing everyone's Pokémon with Mewtwo Balls, Neesha, along with everyone else, did her very best to protect her Pokémon but failed. Later, when her Pokémon were freed by Ash, she watched as her Pokémon, along with everyone else's, battle brutally against their clones. Eventually, Ash intervened and was caught in the crossfire between Mewtwo and Mew, Mewtwo's counterpart, leading to the boy's petrification. After Ash's revival, Mewtwo has a revelation and end the challenge. As a result, Mewtwo wipes out everyone's memories, including Neesha's, regarding the events on New Island. Later, Neesha joined the other Pokémon Trainers and Officer Jenny in watching the storm clear up.
Neesha seems to be in her mid-teen years. She has black eyes and brown eyebrows. Neesha has brown hair too except the hair is relatively short. For clothing, she wears a blue t-shirt with white handles on the top of it. The shirt has a PokeBall design on it She wears a pair of tan long pants with bright brown shoes for the girl's feet.
Neesha is a calm and approachable young woman. She carries herself confidently although she doesn't show off as well. Neesha's streak of determination is most evident during her battle against Mewtwo.
The book adaptation, though usually calling Neesha by her English name, refers to her as "Sweet."