>>55523209Game where you play as Riley's son/daughter and have Riolu as your starter. Riley has you go on an adventure because an Absol showed itself to you, which he interprets as a bad omen indicating that you need to save Sinnoh.
The game follows the Platinum storyline but you're basically inserted in it; both Lucas/Dawn and Barry are your rivals. You can eventually get all three Sinnoh starters through sidequests just like in Yellow.
Riolu doesn't evolve through friendship, instead it does so during a scripted event in the Maylene fight.
During the climax when Giratina appears, Volo comes out and manages to control Dialga and Palkia. You can choose which one you fight and potentially capture, Lucas takes the other. Cyrus and Volo then team up and you have a 2v2 fight against them, including a phase where they control Giratina and Lucas and you control Dialga and Palkia.
When you get to the league, once you defeat Cynthia she does the whole Lance "is what i would say but..." and it turns out Lucas beat the league before you and is now the champion, you go into the HoF room to fight him there as the true final boss, where he will use Dialga or Palkia depending on which one you didn't pick as a co-ace alongside his starter.