The Ghost of Maiden Peak

At a summer festival in Saffron City, Brock and James fall in love with a mysterious girl. Later, they find out that she has been dead for 2,000 years, and believe they saw her spirit. Ash, Misty and Jesse learn that the girl is really Gastly, a ghost Pokemon disguised as the girl to remind people of her legend. Ash, Misty and Jesse battle Gastly to save James and Brock, but come morning, Gastly disappears for another year.