Judging by the fact it's prerendered (that can't be in-game, not on the Wii), I'd say it's the story.
Looks like Mario is tired of the constant fighting, transforms Kirby back, and offers him friendship. Then, since that's against the rules, Metaknight swoops in to enforce the status quo.
It's an interesting idea. I wanna know what happens next. Is the robot thing in the last picture from the Kirby series, or what? I don't recognize it.