they couldve been in the mushroom kingdom as babies/toddlers, had to move to new donk city and grew up there, and then they are brought back to their routes of the kingdom due to a notice of the princess being kidnapped by bowser. the end of the movie could have them decide to move back to the mushroom kingdom and set up for a sequel based on mario 3.That reminds me, I'm concerned about how the Mario Bros.' origins will be handled in the upcoming movie. Based on what we know about the cast, it's looking like it will start out with arcade scenarios such as Donkey Kong and Wrecking Crew before leading them into the Mushroom Kingdom. But that would contradict Yoshi's Island and Partners in Time which showed Mario and Luigi not only living in the Mushroom Kingdom as babies, but also knowing Peach and Bowser as babies. Did they grow up in the Mushroom Kingdom or did they originate in the human world, ie Brooklyn? Or even New Donk City, which would have more of a traditional link to the Mushroom Kingdom as opposed to a warp zone leading there like the old lore had? Whatever the case, something is almost certain to get retconned if they touch on the Mario Bros.' origins so I hope that is done well at least.