Mario stood outside his house in the Mushroom Kingdom, basking in the morning sunlight. He could feel the excitement bubbling inside him as he prepared to embark on another adventure. But just as he was about to set off, a strange disturbance caught his attention. Before he could react, a portal materialized before him, and out tumbled his brother Luigi.
Worried, Mario rushed over to check on his sibling. Something was off; this Luigi looked different, transformed somehow. As Luigi caught his breath, he revealed the shocking truth: he was from an alternate timeline.
In this parallel reality, Mario had strayed down a darker path. Trembling, Luigi explained that a powerful creation called the Tanooki Flower had merged the abilities of both the Tanooki Leaf and the Fire Flower. It was birthed by their timeline's Bowser, now known as Alternate Bowser.
Mario thirsted for more knowledge, desperate to understand the circumstances that led to his alter ego's evil turn. Luigi obliged, recounting the arrival of a mysterious girl named Hildegard. She had fallen from the sky, her memory fragmented save for her name. Compassionately, Mario and Luigi had taken her under their wing, and she joined them on their adventures.
But tragedy struck when, after defeating Bowser for the umpteenth time, a horrifying secret was revealed. Peach, Princess of the Mushroom Kingdom, had been conducting sinister experiments on innocent Toads and even Koopas. And there, at the heart of this heinous discovery, was the lifeless form of Hildegard, her life force incinerated by a Fire Flower that had inexplicably merged with her body.
Alternate Mario was blinded with grief and fury, vowing to punish the Mushroom Kingdom he once called home. With his incredible power, he set out to destroy not only the kingdom but also every Power-up that reminded him of the darkness behind his beloved's demise.
Relieved that his own Mario had only targeted the Mushroom Kingdom and not the entire world, Luigi breathed a sigh of relief. But now the question burned in Mario's mind: why had Luigi been sent to his timeline? Luigi wracked his memory and eventually remembered that Alternate Bowser had neglected to disclose the crucial details.
Suddenly, a hologram materialized before them. It was Alternate Bowser, battered but undeterred. He had survived Alternate Mario's wrath and carried a message shrouded in secrecy. It spoke of something called the Nemesis Trigger, a weapon that could defeat Alternate Mario once and for all.
Mario listened intently as Alternate Bowser explained that the Nemesis Trigger was located at the Eternal Fort in his own timeline. But the task seemed impossible; it was not the right time for them to venture there. It was then that Alternate Bowser revealed the key to their mission: the Time Stone.
Taking on a solemn air, Alternate Bowser instructed Mario to travel to Peach's Castle and slam the Time Stone into the very center of the ground. This act would activate the Nemesis Trigger, putting an end to Alternate Mario's reign of terror.
As the hologram of Bowser flickered and faded away, Mario knew he had no choice but to undertake this dangerous task. He made a silent promise not to disappoint Bowser's final words: "Don't screw this up." With a resolute glance at Luigi, they joined forces and began their journey, anticipation mixing with trepidation.