Pokémon S01E14 - Electric Shock Showdown

Pokemon: Our heroes finally reach Vermilion City. They make their way to the Pokemon Center to refill their empty stomachs, but once there, they witness dozens of injured Pokemon being treated. Pikachu and Ash are alarmed to learn that all of these Pokemon were injured in battles with the Vermilion Gym Leader, Lt. Surge. Nonetheless, eager to earn a badge, Ash challenges Lt. Surge. Pikachu reluctantly enters the battle only to discover its opponent to be a Raichu, its evolved form. After a short battle Pikachu is overwhelmingly defeated. At the pokemon center Ash wonders what he can do to win. Nurse Joy presents him with a Thunder Stone which would evolve Pikachu into Raichu and make it more powerful. Now he must choose whether or not to evolve Pikachu just to beat one trainer.