May’s CoroCoro also expands on the plot of Giratina and the Bouquet from the Icy Sky, Shaymin, providing us with this summary:
Shaymin reveals itself to Ash and friends, but has become weak. Through telepathy, it tells them that Giratina is in a rage and has been pursuing it. Shaymin became accidentally involved in Giratina and Dialga’s battle, but managed to use Seed Flare to defend itself and escape. Dialga also succeeded in escaping due to Seed Flare, and because of that, Giratina began to pursue Shaymin.
The first summary released revealed that because of the battle between Dialga and Palkia, the “Reverse World” becomes polluted. The Reverse World is like a mirror to our own world, but many rules of physics apparently do not apply. Giratina, angry at the pollution, lures Dialga into its realm and begins attacking it, while Shaymin appears to Ash and friends. A movie villain, his android, and a traveling scientist are also revealed, but their roles as of now are unknown.