- Any Boss
Mario wakes up one day and Peach has sent him one of her fabled letters. She is asking him to come over to the castle for a little bit of cake baked by hers truly. Of course nobody can put down the offer of freshly made cake so he takes off for the Mushroom Castle. Before he get there Bowser decides to replay on of his old tricks by locking Peach in the secret room behind the mosaic and then spreading the peices of the key all of the Mushroom Kingdom. As Mario gets there Yoshi explains to him the horror that has befell the beloved princess. Mario vows to save her yet again. Yoshi says he knows valuable information about the insides of the castle so he will follow along for now. As they approach the castle Luigi comes from behind in a frantic. He is running around in circles and screaming that the princess invited him over for cake. Then Wario and Waluigi show up and say the same thing. They've all been invited and now they all have a problem to solve. They all quickly head into the castle to begin their quest.