Yoshi’s New Island

Yoshi's New Island was the second kidnapping of Baby Mario & Luigi after they were accidentally delivered to the wrong parents.

History
Right after Super Mario World 2: Yoshi's Island, the Stork accidentally delivered Baby Mario & Luigi to the wrong house. Taking the babies again to deliver them to the right house, they are ambushed by Kamek and the Toadies again. While they managed to nab Baby Luigi, Baby Mario landed on Egg Island, a floating paradise and a peaceful second home for the Yoshi clan, but has recently been taken over by Baby Bowser.

The Yoshi Clan on that island were discussing where Baby Bowser's castle might be but are interrupted by Baby Mario's landing. Using some form of brotherly telepathy, Mario could sense Luigi's location and crawled right where he is. The Yoshi's, knowing this island is too dangerous for a baby, decide to carry him towards his destination.

All throughout the journey, Kamek would appear in each castle and try and persuade the Yoshi clan to hand over Baby Mario. One method is him enhancing enemies using a magic hammer on enemies, making them a much more formidable threat to the Yoshi's.

The Yoshi clan and Baby Mario were also joined by a mysterious individual named Mr. Pipe. He would appear to lend the Yoshi clan items before leaving.

After finishing Crumble Rock Rumble, the Yoshi's have managed to find the location of Bowser's Castle; right on the side of Egg Island. One Yoshi enters, passes through its defenses, and makes their way into Bowser's room. After a small tussle, Kamek enhances Baby Bowser, turning him massive. Despite that, the Yoshi perseveres in defeating Baby Bowser.

Suddenly, warping through space and time, King Bowser from the future appears. Another fight ensues, and Kamek appears again to make him massive, but that still wasn't enough to best that Yoshi. The Bowser from the future leaves via a bright ball of light into the vortex in the sky, and Baby Mario is reunited with Baby Luigi and the tied-up Stork. Egg Island is released from Bowser's control.

The Stork finishes his destination and the Baby Mario Bros. are delivered to their parents. "For real this time." Mr. Pipe himself exits his disguise, revealing it was none other than the future Mario himself. He jumps up, also disappearing into that same ball of light.

Timeline

 * Begins right where Super Mario World 2: Yoshi's Island ended.
 * Mario & Luigi are delivered to their home in the end.