This trailer shows that it’s not that at all.
It starts out the same, but apparently after seeing Ho-Oh, Ash meets up with some entirely new characters with Pokemon from other regions who also have Rainbow Wings from Ho-Oh, and in a surprisingly soon reveal, the 802nd Pokemon Marshadow appears to guide them to the mountain where Ho-Oh lives. Serebii’s translations mention becoming “Heroes of the Rainbow” and Ash and Pikachu learning to become partners to defeat some powerful opponent. Also there’s a shot of an old man with a hat that looks suspiciously similar to the one Red wears. Yes, that Red.
My first reaction was “How can you go for a nostalgia cash-in while taking away virtually all the stuff people are nostalgic for?” Then I remembered one of my initial complaints was that “Movies that retell arcs are boring” and realized I actually like this development. I probably shouldn’t get my hopes too high, but there’s a chance for a rather interesting story here, and I’m looking forward to seeing if it delivers.
But since this is giving us the Pikachu with the hat and Marshadow, that means we’ve already hit the bottom of the Gen VII event Pokemon well…which has me…worried…