This is a basic summary of the main events of the game, not the whole complete story.
So Kirby was walking around the grass world, and he saw something shiny. It was aqua blue, like a 3DS. And it was! Kirby picked it up, excited. There was an image of King Dedede on it, and under the image it read ENEMY APPROACHING. Sure enough, Dedede was sneaking up on Kirby, ready to attack. Kirby engaged in battle with the king, and Kirby obviously won. King Dedede stormed off, grumbling to himself. Kirby smiled, held the 3DS in his hand, and walked off.
He found Meta Knight, who was now engaging in battle with Dedede. The screen read ENEMY RIGHT THERE. ATTACK? There were then two buttons, YES and NO. Kirby hit 'yes'. The 3DS shot light beams at King Dedede, who yelped in pain. He ran off, yelling at Kirby. Meta Knight walked over to Kirby and gave him a little pat on the back. Then the two walked off.
As Kirby expected, Dedede was in battle with someone else. Kirby and Meta Knight simply hit the king once, and he ran off. The people Dedede was beating up was his own two minions, Bandanna Dee and Waddle Daa. They joined Kirby and explained that they wanted to run away from the king's clutches of being servants. The four walked around, ready to clear levels and beat Dedede once and for all.
There'll be Mini-Bosses like the other games. Those consist of people like Bonkers and Shadow Kirby. They can be found in any level, about one or two a world. They give Kirby a copy ability when defeated.
In boss levels, Kirby fights not one but TWO bosses. Surprised? You should be, since it's a new feature! In the boss level of a world, Kirby fights a boss around the middle of the stage, goes through the rest, and fights the End Boss.
The final boss of a world. Much harder than Mid and Mini bosses, obviously. Once defeated, Kirby gains a key, which opens a pathway to the next world.
I think I'm done. But one last thing.
The 3DS holds many secrets. There are different rooms that you can enter in it. There are rooms for cheat codes, power-up testing, and even an enemy gallery. (Did I mention that Kirby enters the 3DS?)
So that's all for now. And so for now, it's SDMK out!