Delfino Plaza
Exiting out of the Shine Sprite portal from the lighthouse on the east side of Delfino Plaza, Mario wiped his brow of sweat; just as he was about to head to the next area to collect more Shine Sprites, an explosion echoed at the main plaza, follow by puffs of flames and fire erupting into the sky in the general direction of said explosion. "Mario!" Princess Peach could be heard yelling for his rescue.
"Uh oh!" Mario remarked as he made a mad dash for the main plaza where the chaos was happening, and as he was running as fast as his feet could take him, the locals ran in the opposite direction of him as he ran through the fruit vendor street. Another explosion boomed from the main plaza, followed by the sound of machinery, wheels, and buzzsaws.
As Mario ran around the corner bend and into the main plaza of Delfino Plaza, a particular sight baffled him; Princess Peach was held captive by Bowser's adviser Kamek within a Koopa sub, with its top hatch open, that was docked next to the edge of the plaza, all the while Bowser himself is seen fighting against Bowser Junior who was inside a Miniature Clown Car, the likes of which reminded Mario of the time he fought against Bowser on Dinosaur Island, in which Bowser used a larger size Koopa Clown car to ride on and hover during their fight against each other.
Back to the matter at hand as Mario witnesses a little family feud of sorts as Junior is seen revving up his Clown Car, before making a burnout and zooming off towards Bowser with mechanical arms out at its side with razer saws on them, "Stupid pa! This isn't supposed to be about you!" He shouted childishly as he drove his clown car at his own dad.
"Junior, you've had your fun, now it's time to take Peach!" Bowser retorted back as he pulled his hand back, and swung it at his incoming belligerent son; with a loud thwack and clang of Junior's clown car getting whacked aside, Mario watched as the little Tyke get launched up into the air before landing back down into the nearby fountain pool.
"Mario. I see you've been keeping my son occupied." Bowser began to talk to Mario as he faced his arch nemesis with a smirk
"But playtimes over, I'm taking Princess Peach to enjoy a nice vacation with her, and there's nothing you can do about it! Bwaha!" Bowser monologues while Mario makes a mad dash for Princess Peach, only to find his path blocked by a ring of fire from Bowser breathing it out to block him off from saving Peach, while at the same time making an impromptu boss arena for Mario and Him.
"I just need to get you out of the way!" Bowser finished saying, before he leapt up into the air, performed a body slam in the direction where Mario was at.
Acting quickly, Mario dove out of the way and slid along the ground as Bowser's body slammed into the spot where he once was; As Mario picked himself up off the ground, both he and Bowser were standing up to fight against each other.
Just before both combatants could make a move however, from over the hills and through the air above the buildings, in came a flying mech; At first Mario thought it was a bowser mech of sorts, but then he thought differently when the color scheme was all wrong. While Bowser's attention was focused on the flying mech as well, it allowed Mario to further get a good look of the flying turtle shell mech as it soared over the rooftops with twin jets on its backside.
As the turtle shell mech flew down to the ground, it swooped in direction where Junior was sent into the nearby water fountain pool was, and continued flying with a passenger hanging onto the bottom of the flying turtle shell meck; Bowser Junior managed to latch onto the incoming mech, and carried out of his predicament within the pool of water he was in. As the mech circled around in the air with Junior hanging onto its bottom, the mech flew in the direction of the impromptu boss arena of fire; as the mech flew towards the arena, both it and Bowser Junior flipped through the air, and landed beside Mario with a big thump on the ground.
Now strapped inside the mech that towered over Mario, but just barely reach half the height of Bowser at present, Junior sat within the center of the oversized shell that protected his backside; Twin Cannons poked out of two holes of the shells, while it stood on blue mechanized legs. Junior tested a few controls by making his mech's blue arms curl and clench its claw digits.
Junior lifted out his arm to point at Bowser. "You put Princess Peach back, Pa! You promised me I could do everything on isle Delfino, but here you are kidnapping Princess Peach!" Bowser Junior accused his Pa.
"Junior!" Bowser began to growl, "This doesn't concern you! Go back and sit on the sidelines like a good kid." he tried to scold his child while pointing in the direction outside the circle of flames.
In response to Bowser's order, Junior simply pressed a button within the controls of his mech, before shortly after, the turtle mech bent forward and blasted out a pressurized spray of water at his own father, "Sideline this, pa!" Junior said back as Bowser found himself knocked back out of the circle of flames and on his back from the sheer force of the water pressure.
While Bowser was busy picking himself up off the ground to deal with both his son and Mario at the same time, FLUDD spoke back in a curious tone. "Junior, was that blast of water the same type of technology as what makes me?" she queried as Bowser stomped his way towards the ring of fire boss arena.
Bowser Junior smiled excitedly as he glanced down over at Mario and FLUDD, "Yeah! Like it? It's my Blastoise Mech! It's a Mark One version so far, but with a little tweaking, I-" Junior gushed about his achievement, but was cut off by Bowser as he stomped through the flames.
"Junior, very well then! I'll take you both on, and show you how a true Koopa King fights! Consider this your first actual spar against your own Dad!" Bowser boisterously announced with a menacing grin, and flames exiting out the sides of his mouth.
"Mario, I believe it is prudent to consider the child's temporary alliance against Bowser." FLUDD suggested to Mario.
"Right!" Junior responded with an excited smirk, "Temporary! But after this, we'll be back to being enemies, that is if we can stop my dad of course from taking Princess Peach." he added.
Mario nodded with a resolute look in his eyes, as both he and Junior rushed in at Bowser as the Koopa King roared back at them.
With the jet thrusters of Junior's mech at full throttle, the turtle shell mech flew up and forwards towards Bowser, with water missiles being shot out its side while the mech fired off low pressure shots out its cannons; While Junior occupied the frontal assault on his own dad, Mario ran in from the side to make for the tail and grab for it. As Bowser spluttered water out of his mouth and nostrils from the impact of the water missiles and incoming fire of water blasts, Junior withdrew into the large shell to knock over his dad.
The force of the impact sent the Koopa King tumbling back and onto his shell while Junior flew his mech up and around the arena, while Mario was given the ample opportunity to get a clear shot of grabbing Bowser's Tail; With a heave, Mario pulled on the Koopa King's tail and began spinning up around. After a good windup, Mario Released Bowser to go flying into a nearby buoy in the ocean; with a loud ding a splash, Bowser hit the buoy and sank into the ocean.
Within the nearby Koopa Sub, Kamek and Peach watched it all happen from the sidelines; While Peach was rooting for Mario to come out on top and win to save her, Kamek on the other hand was conflicted as he watched his liege get double teamed by Mario and Bowser Junior. "You can win this, Sir!" Kamek cupped his mouth for his liege to hear him, only to find his wizard cap pulled over his face.
"Shut it, you!" Peach grumbled as she brushed her hands off against each other.
Back within the circle of flames, Mario waited for Bowser to come back out of the ocean, and fight him once more, all the while Junior landed his Mech next to him. "No way that did my pa in." he commented with his brow furrowed as he looked in the direction of the ocean where Mario sent his father, Mario couldn't help but nod in agreement.
From out of the ocean, Bowser surfaced with a triumphant look, "Not bad, but now I have you right where I want you, while I take Peach!" he boasted, while within the sub, Kamek pulled his hat off from over his face to see, and took what his liege said as the go ahead to get going. With a slam of his wizard staff into the floor below him, the open hatch closed both him and Peach off from the world, and allowed the sub to delve down underwater.
Bowser then dived under the ocean, leaving Junior and Mario stranded within the circle of fire leftover from the mini-event.
"You know…" Bowser Junior began to say as he fired off his mech's cannons to douse the flames around the two of them with heavy amounts of water, "I should have seen that coming, but I guess dad was just one step ahead of me." he mused.
FLUDD meanwhile, had her own two cents to add, "Junior, what will you do now?" she questioned him.
As Junior finished dousing the circle of flames down, he turned his turtle mech around with a smirk. "I don't know about you two, but I'm not about to let my Pa get off scot free on this." he answered, before unclasping himself down from the mech, and landed on his feet to stand across from Mario on his own two feet. "Pa stole my Thunder, I think I'll go the usual cliche route and end up as an ally for the second phase of the game." Junior explained with an excited smile.
"Game?" FLUDD questioned, "What game do you speak of?" She asked from over Mario's shoulder.
"..." Bowser Junior blinked a few times in silence, before focusing on Mario, "Isn't that how it is, between you and pa, Mario?" he asked with a confused look. "I mean, pa has said in passing he's competed against you in many games and parties, right?"
Mario nodded, in finally understanding some bits of info that might have been mixed up, but erred the side of caution to not tell the child that those games and parties were different compared to other times when Bowser actually kidnapped Peach; More often than not, the stakes were high, especially when he had to go through multiple world levels.
"So, Truce until Princess Peach is saved?" Junior asked as he looked up at Mario with his hand out to shake on it.
"It's-a Truce then." Mario responded as he reached out and shook on it with Bowser Junior.
"Oh, and I'll probably end up betraying you if it ever comes down to it." Junior added with a bright smile, earning a confused look from Mario as they finished shaking on the temporary truce, "What? Pa always said, 'a real good villain, never lies, but may omit the full truth'." He reasoned with a toothy grin.
Now Mario was wondering what sorts of things Bowser actually taught his son.