When Princess Peach catches Luigi handing the castle's secret defense blueprints to Bowser Jr., mass panic erupts. To save his terrified brother from execution, Mario steps forward and falsely claims full responsibility for the betrayal. Furious and heartbroken, Peach strips Mario of his hero title and banishes him into the stormy badlands. While in exile, Mario uncovers evidence that Bowser Jr. ruthlessly blackmailed Luigi. Mario secretly infiltrates Bowser's flying volcanic Dreadnought, destroys the warship from within, and recovers the stolen plans. Upon learning the truth, Peach restores Mario’s honor, reuniting the unbreakable brothers as the realm's true protectors.