The trailer showcases Ash and Pikachu in Pallet Town; the poster features Ho-Oh. Ash is seen in his original clothes, though the art style is slightly different. Could the movie be recapping Ash’s first adventures? It is the 20th anniversary of the movies, after all. Maybe we’ll learn more about Ash’s history, perhaps about his father? /wild speculation
The movie will be released in Japanese theaters on July 15th.