A/N: So, what is this? Well, it's an idea that came to me out of nowhere. I've been reading a lot of Mario fanfics lately and felt inspired to write a new one myself.

I have the next few chapters of this already done, so I unless I get really stuck, updates shouldn't be too slow. Also, just a warning: this story does contain some violence and mild swearing.

Reviews are hugely appreciated! I have no idea how long this'll be, but it's going to contain multiple chapters, so it would be great to know what everyone thinks of it.

Enjoy!

Bowser let a grin curl up his massive jaws as he watched Mario and Luigi – Luigi! - walking into his throne room. The two brothers were sticking close together were gazing around a little nervously, as if expecting their enemy to jump out from behind one of the engraved pillars.

After letting them wander around in the dark for a minute or two, Bowser turned to Kamek, who was standing behind him. 'Light the torches, Kamek,' he growled. 'Let them see that we're here.'

'Yes, sire.' With a casual flick of his wand, the magikoopa caused all the torches along the walls to explode into orange flames, illuminating the throne room.

Luigi jumped. 'M-Mario!' he said, pointing a shaky finger up at the throne, which rested atop a platform surrounded by red-carpeted stairs. 'There!'

Mario whirled around, his face locked in a determined scowl. Bowser observed them both quietly for the moment, then laughed and jumped down from the platform, landing with a thud that rattled the torches. He could tell that the brothers were thrown off by his more unusual entrance. Most of the time, he would simply lure Mario into his castle before viciously ambushing him in a whirl of fire and claws, only to be beaten down due to his recklessness. But this time, Bowser had taken all his previous losses into consideration and was absolutely certain that he'd win...

He'd made a plan; a cunning and devious plan that had caused Kamek's face to light up with surprise when he explained it. Instead of just kidnapping Princess Peach as usual, he decided to kidnap Princess Daisy as well. By taking both princesses, he managed to lure both of the hero brothers to his castle. That was stage one of the plan.

Stage two was to take out Luigi first; he was so weak and inexperienced that Bowser didn't expect to have any problems with him at all. He'd take care of the green guy, and Mario would be so shocked and distraught at seeing his little brother defeated that he would be an easy target for Bowser's attacks. It was an infallible plan, and the King had never felt more proud in his life.

'Up and at 'em, sire,' whispered Kamek in his dry, raspy voice. 'Show them that you're the one who deserves to rule the Mushroom World!'

With a triumphant roar, Bowser sprung forwards. The two brothers were forced to scatter in opposite directions to avoid his charge, with Mario running to his left and Luigi to his right. The younger brother stumbled on a loose bit of stone in the floor, and instantly Bowser was upon him, changing the direction of his charge and throwing himself upon Luigi like a tidal wave. Luigi didn't realise he was being targeted until it was too late.

'MAAAARIIOOOOO!' he screamed as Bowser's swiping claws knocked him aside. He was thrown to the floor, quickly rolling away to avoid the foot-stomp that came a second later. 'OVER HEEERE!'

'Shut up, you twerp,' Bowser growled, kicking him. Then, while Luigi was briefly dazed by the blow, he brought his foot down on the young man's leg, hard enough to snap the bone in half.

The crack that resounded throughout the throne room made Bowser wince despite himself. He'd never managed to get close enough to Mario to hurt him in such a way, and if he were honest, he didn't enjoy it as much as he expected to. But Luigi's scream tore all other thoughts out of his mind.

Suddenly, a body threw itself at Bowser from behind, leaping onto his shoulders – barely missing the spikes on his shell – and driving a fist into the side of his head. Caught off-guard, Bowser staggered, and Mario was able to knock him to the floor with another punching blow that seemed too powerful to have come from someone so small. His face was contorted in rage, and Bowser realised with an unfamiliar twinge of fear that this might be the last time he ever fought his arch-rival.

'K-Kamek,' he gasped out, uncertain if the magikoopa would hear him, 'release Peach! Quick, now!'

He struck out blindly with his leg as Mario bore down on him, and felt a wave of relief when he felt the blow connect and shove Mario backwards. He was vaguely aware of another sound; a broken sobbing coming from the place where he'd left Luigi lying on the floor, but he ignored it and hauled himself to his feet, snarling furiously at his arch-rival.

As he got up, an idea came into his head – an idea so awesomely evil that Kamek might have cried tears of joy if he'd gotten to hear it. Bowser's snarl slowly turned into a mocking grin as he stepped backwards, positioning himself directly in front of Luigi, who was clearly in no condition to move.

'Game's up, Mario,' he said. 'I've got your stupid, useless little bro. What are you gonna do about it?'

Mario hesitated. He had been about to charge, but now he stopped, afraid that he might cause Bowser to hurt Luigi again if he moved. As the two enemies faced each other down, a sound from the other end of the throne room prompted Mario to glance up.

'Mario!' a voice cried. It was Peach, released from her cage and running towards him.

'Princess!'

Bowser's grin widened. 'Your choice, buddy. Her... or your brother.'

Mario's face went slack. 'I...I...'

'Come on, I don't have all day.'

Just then, Peach caught up to Mario and grabbed his arm, looking terrified. 'What are we going to do?' she whispered. 'Don't tell me you're thinking of leaving Luigi behind! He's your brother!'

Mario shook his head slowly. He looked lost. 'I-I can't leave him... but I can't leave you even more.'

Bowser tapped his foot impatiently for dramatic effect. 'Time's running out, plumber boy!' he growled. 'Hurry up and decide! If you choose to leave this idiot, then I'll let you and Peach escape with your lives.'

Deep down – so deep that he could pretend it didn't exist – he felt something that could almost be described as... sympathy? No, not that, surely. But maybe a hint of pity. Everyone was looking at Mario like he was the one who had it hard, but Peach was the one who'd been kidnapped, and Luigi was the one currently crying in pain on the floor.

And it was up to Mario to decide; leave Peach behind to be held hostage by Bowser, possibly forced to give her kingdom to him or even marry him, or leave Luigi behind to die. It was an impossible choice. The princess he loved – who cherished her kingdom and would never want it to fall into Bowser's claws – or the little brother who depended on him so much.

With a wretched expression, Mario fastened his hand over Peach's wrist and ran for the exit without a backwards glance.

'...And he left his brother behind,' muttered Bowser, as if he were narrating a story. 'Pitiful. Seems like he cares more about his rich girlfriend than his own family...' He slowly turned around to gaze upon Luigi, who was still lying sprawled on the floor in the same place Bowser had left him after breaking his leg. He had managed to stop crying now, but his eyes were scrunched shut in pain and he was breathing in small, sharp, shallow gasps. Against his better judgement, the King knelt down and poked the young man's shoulder.

'He's gone, you weakling,' he said. 'He's gone with Peach and if he ever shows his ugly face here again, he sure as hell won't be getting you back. Or Daisy, for that matter. I'll be ready for him next time.'

He didn't expect Luigi to try and talk, so he was surprised when a tiny voice spoke up, tense with pain and fear. 'H-h-he'll be back... he won't just l-leave me here. A-and he'll want to save Daisy, too.'

'Ha! And what makes you so sure I'll let him do that?'

'H-he's always beaten you before,' Luigi mumbled.

Bowser pushed his face closer to Luigi's, making him flinch slightly. 'Listen here, pipsqueak,' he snarled. 'Mario didn't win today. He got Peach back only because I let him! And he failed to save Daisy or you, so that's a failure in my book.'

'He g-got Peach, that was the important thing.'

Bowser frowned and quickly tried to hide it behind a scowl. Was Luigi implying that he wasn't important? Or at least, not as important to his brother as Peach was? That couldn't be true... but maybe it was. After all, Mario had chosen to leave his brother behind and rescue his girlfriend instead. That little twinge of pity that he'd felt before rose up like bile in his gut, unwanted, making him angry again.

He stood up. 'Kamek! Help me move this little idiot into a cell. He can be with his beloved Princess Daisy.'

Kamek hurried across the throne room as fast as his arthritis would allow. 'Yes, sire. Is he to be treated with care?'

Bowser considered. Now that he had Luigi in his grasp, there were a thousand different routes he could take. Countless possibilities, most of them revolving around using the young man as a bargaining chip to force Peach, and maybe Daisy as well, to surrender their lands to him... But whatever he decided to do, he needed Luigi alive.

'Yeah, you'd better be careful with him,' he said. 'He's not gonna be much use to us dead.'

Kamek nodded and swiftly conjured what seemed to be a magical, luminescent stretcher hovering above the floor. Another wave of his wand brought Luigi levitating upwards to rest gently on the stretcher, where he lay motionless, his eyes flicking between the magikoopa and the Koopa King with terror clearly written in them.

'Take him away,' said Bowser, 'and give him whatever medical attention he needs. Then put him in cell number 14 – the one right next to Daisy's.'

Kamek bowed his acknowledgement and shuffled away, the magical stretcher floating along beside him seemingly of its own volition.

Bowser remained standing in the empty throne room, watching them go. He wondered what was going to happen now, and was surprised to realise that he wasn't thinking about how he could use Luigi to take over the Mushroom World, but instead whether or not Mario was going to come back for his brother.