You were guarding the Power Star, as you were tasked to do. You were just watching on guard for anything, until... BOOM, the wall was destroyed, and a bunch of Koopa Troops with spears appeared and pointed their spear at you. That's when Bowser came in, with a huge menacing smile

"Bwahahahaha! They let someone like this pipsqueak guard the Power Star?! Oh well, I'll just take them with me!" Bowser then grabbed you and hoisted you over his shoulder, before grabbing the Power Star, and taking you back to his Flying Castle