Pikachu no Natsumatsuri(2004)

Pikachu no Natsumatsuri

Summer has arrived, and many Pokemon have set up shops for a summer festival on the beach. Soon the gang will be blessed by a special performance from the pop idol Azumarill, but upon her arrival, she's kidnapped by the flying Pokemon Skarmory! Pikachu, along with Plusle, Minun, Meowth, Wobbuffet and a number of other Pokemon must now track down the singing beauty; the show must go on!

(Source: Anime-Planet)