There's another problem in the Mushroom Kingdom! Baby Peach, instead of Peach has been kidnapped! Now it's up to Mario his brother and they're sons to rescue Baby Peach from the evil clutch of Bowser!
Mario was outside in the castle courtyard where suddenly from above him, Baby Peach comes flying down in a Bowser Airship and starts crying. Mario's kid, Baby Mario and Baby Luigi, Luigi's kid, run into the courtyard playing.
Just then, a note landed on the ground.
BWAHAHAHA! I made a totally diffrent plan! Be prepared for a villainous team! You won't win this time! HAHAHAHAHA!!!
Mario leaves the castle on a great adventure!
The first boss is Bowser Jr.. To defeat him, there are platforms. To stay alive, move to one that won't be blown up. The platform that doesn't glow, won't blow up. Then after that, you step on a electrical platform to shock him. After you blow his last HP, he runs off to his clown car, and flies back to the castle.
By this point you should've picked up Goombella.
After a couple levels through the Warp Pipes, Mario and Luigi meet up with Dino Pirhana. Dino Pirhana stands above 3 portals. Mario, Luigi, and Goombella guess through the portals which one leads to the portal next to Dino Pirhana. You attack Dino Pirhana with a special combo done by all 3. After doing that about 10 times, Dino Pirhana runs through the Warp Pipes back to Bowser's Castle.