Poor Ash, after all his hard work of failing at every league ever and generally having amnesia attacks at every new region - oh and his Pikachu going like "fuck it" and going back to Level 5 because YOLO #PikachuLogic and this is what Ash gets for all the shit he goes through. Being an old professor who sits behind a computer all day giving empty Pokedexs to 10 year old girls and boys wanting to start their Pokemon Journey. Ash follows them like a stalker to tell them that no, they can't use a Bicycle in doors because Ash stalks for the law. Ash then finds his real father who turns out to be Greninja all along (hence why they can become ASH-GRENINJA!!! (really at this point anything is possible)).