Mario and Luigi walked into the throne room. Multiple chandeliers hung from the ceiling, and several Bowser statues were placed at equal intervals between the entrance and back of the room. A red carpet draped the stone floor and led straight towards the throne, which Bowser was seated in!

"What?!" Bowser exclaimed. "Mario! And…that other green guy! What are you doing here?!"

"We need something from you!" Mario said.

"Well, the princess is in the dungeon, and if you want her back…wait a minute, I haven't even kidnapped the princess!" Bowser exclaimed in confusion.

"We need that Crystal Star you have!" Luigi said.

"Wait…Crystal Star?" Bowser asked. "This?" Bowser pulled the Diamond Star out of his shell!

"Exactly!" Mario said.

"You can't have it!" Bowser said. "This thing just suddenly flies into my castle and hits me in the head! As I pick it up, this blinding light shoots out from it, and suddenly I feel completely energized! And now that I realize it's a Crystal Star, no way I'm giving it up to you after all the trouble I went through to try and nab one in Rogueport! After I defeat you, I'll head out and find the rest of them!"

"Not if we have anything to say about it!" Mario said. "Let's-a go!"

Mario and Luigi took out their hammers and jumped at Bowser. Bowser roared and jumped at Mario and Luigi. The three collided in midair and started dueling, Mario and Luigi smashing at Bowser with their hammers and Bowser clawing and punching at the Mario Bros. Eventually, Bowser pulled back his arm and slammed Luigi in the face, sending Luigi flying backwards. Mario tried to hammer Bowser's arm, but Bowser pulled back and uppercut Mario with his other arm. Luigi got up and threw his hammer at Bowser, but Bowser caught it by the handle and threw it back at Luigi. Luigi freaked out for a second before diving to the left, just barely avoiding getting hit. Mario ran at Bowser and delivered an uppercut to the Koopa King's jaw, knocking Bowser back onto his shell. Mario and Luigi then jumped up into the air together and slammed down onto Bowser's stomach, knocking the wind out of him.

Bowser roared in pain and anger as he got up and jumped backwards. Bowser began shooting multiple fireballs at Mario and Luigi. The Mario Bros ran up the hallway, dodging and jumping over the fireballs as they went. Mario reached Bowser, jumped up in the air, and prepared to do a meteor smash, but Bowser sidestepped the attack, causing Mario to slam into the floor. Bowser then grabbed Mario and threw him into Luigi, causing both brothers to be thrown into the back of the room.

"Gwahahaha!" Bowser laughed. Mario and Luigi groaned as they got up. Mario took out his hammer, looked at Luigi, and nodded. Luigi nodded back and moved right in front of Mario. Mario then smashed his hammer down onto Luigi, causing Luigi to burrow into the floor. Mario then jumped towards Bowser while Luigi moved underground. Bowser prepared to counterattack, but as soon as Mario got in range, Luigi popped up from above, propelling Mario upwards! Mario then swung his hammer around multiple times in succession, smashing Bowser across the face each time! "Augh!" Bowser said as he stumbled backwards. Taking advantage of their enemy's weakened state, Mario and Luigi performed another attack. Mario handed Luigi his hammer, and Luigi smashed the hammer into Mario, shrinking Mario to half of his normal size. Luigi then swung the hammer into Mario like a golf club, shooting Mario towards Bowser. Mario smashed into Bowser's head with extreme force, causing the Koopa King to roar out in pain and fall forward onto the floor in defeat.

"Alright!" Mario and Luigi cheered for themselves in victory.

"No…" Bowser mumbled. "I didn't just get beaten by Mario…again…"

"You sure did!" Mario said. "Now, cough up that Crystal Star!"

"I don't think so," Bowser said. "Koopalings, catch!" Bowser took the Diamond Star out of his shell and threw it back towards the throne. Just then, the Koopalings magically teleported to that area, and Ludwig caught the star!

"Oh no!" Mario and Luigi exclaimed.

"Haha!" Ludwig laughed. "Sorry, Mario! Looks like we've got the Diamond Star!"

"Yep!" Lemmy continued. "And while you can beat us one on one, there's no way you can beat all seven of us at once!"

"Not that you shouldn't try!" Roy said, cracking his knuckles. "I've been itching for a fight recently!"

Suddenly, a voice said, "Allow me to accept that challenge on their behalf." The Diamond Star was suddenly teleported away and replaced with a Bob-omb! The Bob-omb promptly detonated, sending Bowser and the Koopalings flying away! In their place, a tall shadowy figure materialized.

"Who are you?" Mario asked.

"I'd think you would know," the shadowy figure said. "After all, we've met before."

Mario thought for a moment, then said, "You're one of the guys who attacked our house!"

"Precisely. The name's Shadow Luigi, and I'll be taking this Crystal Star."

"S-shadow Luigi?" Luigi repeated.

"Yep," Shadow Luigi said. "I'm a dark version of you from a dimension parallel to this one. We've come to take over this world and convert all of its inhabitants into shadows like us."

"Wait, we?" Mario repeated. "There's more of you?"

"A lot more," Shadow Luigi said. "There's an army of us. You don't stand a chance."

"Then what do you need the Crystal Stars for?" Mario asked.

"That's better kept a secret," Shadow Luigi said. "Now, unless you surrender, it's time for you to be destroyed."

"You wish!" Mario said as he and Luigi got into fighting positions.

"If it's a fight you're looking for, then it's a fight you'll get," Shadow Luigi said. "I'll let you attack first." Mario leapt at Shadow Luigi and smashed the hammer down onto his opponent, only to find that the hammer had hit nothing but thin air. Mario looked behind him and saw Shadow Luigi standing there. Mario hopped towards him and spun around with his hammer outstretched, doing a horizontal attack, but Shadow Luigi teleported behind Mario and smashed his fist into him, sending Mario flying away. Shadow Luigi then teleported to where Mario was, grabbed Mario and threw him into a wall. Mario slumped to the ground, but quickly got back up, only to see Shadow Luigi standing right there. Shadow Luigi grabbed Mario and threw him towards the middle of the room, but while Mario was still flying, Shadow Luigi teleported just in front of him and kicked Mario upwards. Before Mario could hit the roof, though, Shadow Luigi teleported above Mario and smashed his feet down into him, sending Mario flying downwards. A small explosion occurred as Mario smashed into the floor, leaving a small crater.

"Mamamia…" Mario groaned as he fell unconscious.

"Mario!" Luigi screamed. He looked at Shadow Luigi and took on a fighting position, determined to defeat the person who had harmed Mario. Before Luigi could do anything, though, Shadow Luigi teleported in front of him and punched him backwards! As Luigi flew backwards, Shadow Luigi continuously teleported to Luigi and punched or kicked him, sending the hero flying ever further until he smashed into a wall, sending cracks through it. Before Luigi could even fall to the ground, Shadow Luigi grabbed him by the shirt and slammed his fist into Luigi's face, before slamming him down onto the ground, jumping into the air, and smashing his feet down onto Luigi's back, knocking Luigi out.

"Heh," Shadow Luigi chuckled. "Not even a challenge." He took out the Diamond Star and said, "Now, time to get this back to the boss…"

Suddenly, a red blur shot by, grabbing the Diamond Star! "What?!" Shadow Luigi shouted. He looked to where the red blur was, and saw Mario standing there, Diamond Star in hand! "How?! I knocked you unconscious!"

"Yeah, you did," Mario said. "Good thing I had a Life Shroom on me!"

"Grr…it doesn't matter," Shadow Luigi said. "I'll just beat you unconscious again!" Shadow Luigi teleported behind Mario, but Mario anticipated this and swung his hammer behind him, hitting Shadow Luigi across the face and knocking him to the ground. Mario then smashed his hammer onto Shadow Luigi's stomach, knocking the wind out of him. While Shadow Luigi was temporarily stunned, Mario jumped backwards and held up the Diamond Star. The Diamond Star expanded in size, and Mario jumped up onto it. The Diamond Star jumped up into the air; at the apex of its jump, Mario jumped up and ground pounded down onto it, shooting it down into the ground and causing an earthquake to shoot out. Mario repeated this multiple times, the earth tremors getting more powerful each time, until Mario did one final ground pound, knocking the Diamond Star into the ground and creating a massive tremor that flipped Shadow Luigi up into the air, smashed him into the roof, and caused him to fall back towards the ground.

"Agh…" Shadow Luigi muttered as he got up. "That…wasn't how I planned for this to go." He regained his composure and said, "It doesn't matter. There are still five Crystal Stars out there. Let's see who can get them first." Shadow Luigi teleported away.

Just then, Luigi woke up. "Mamamia…what happened?"

"Thanks to that Life Shroom we got earlier, I did it!" Mario said. "We got the Diamond Star!"

"Alright!" Luigi said. He and Mario high-fived each other. "Where next?"

Just then, the Diamond Star floated out of Mario's hand, and the Magical Map floated out of Mario's backpack. The Diamond Star shot a beam of energy into the Magical Map, then floated into Mario's backpack. Mario grabbed the map and saw that an X was engraved on it in a location far to the north.

"Where's that?" Luigi asked.

"The Shiver Region," Mario said. Mario put the Diamond Star in his backpack, and the two brothers left Bowser's Castle.