Reaching the pump room, the guard was right in how the waste disposal was oddly nearby, and how it offered an easier passageway into the sewers via a direct chuteway.  But first they examined the map which was on the pump room walls.
The pump room itself was merely the large storage tank to keep the place running with fresh water, a massive machine that took up an entire room the size of a squash court.  A large turbined wheel made water rush and roar inside it, with a chart on the wall explaining where every single pipe went to.
	"Here," said Manbat, "the waste disposal is the same as the pump, they follow each other's routes."
	"Isn't that kinda...unsanitary?" asked Sam cautiously.
	"Only if the pipes mix, which they never do."
	"Thank goodness for that, Max has been drinking from every tap in this place."
	"I'm trying to set a Ghostbusters drinking record!" cried out Max.
	"Max, I can't even begin to tell ya how moronic that is, but since yer not harmin' anyone, go nuts.  Uhhh...you DID get a rabies shot right?"
	"I sure hope so!"
With James' nervous glance at Max, the four headed to the waste disposal section and found sure enough, a direct sewer opening for maintenance purposes.  The smell was not something to envy and soon James whined:
	"Are we seriously going into the sewers, through the waste chute?  Sewers are like the worst part of any place!"
	"That's why they're called sewers kiddo," quipped Sam as Manbat went in first.
The masked vigilante grappled the walls to avoid the water, while Sam and Max jumped in second, with James gingerly coming third.
The place was not as terrible as expected, perhaps because it had been rarely used since its opening due to the place being rather new in design.  Traipsing through the slightly dank tunnel, they navigated through corridors and crossroads, guided by Manbat's sonar to detect the main drain, the largest room and the most likely source for the Daleynium quarry.
After a grumbling small while of traversing pipes, they finally reached the main drain, which was actually more of a cavern.  A huge sprawling cavern where waste water was sent back to the sea and the lakes via large waterfalls, the continuous sound of rushing water keeping the place without silence.
	"This...is a big place," said James in a rather awestruck tone.
	"You could fit the entire ego of Javier Bardem in this place," said Sam.
	"Wasn't he a cat with shoes in some animated thingy?" asked Max.
	"Wrong Spaniard, Max."
	"Joke Rat is here," said Manbat.  "We must climb to the top."
	"Pssh, fine by me," said James as he rubbed his claws together before they heard a rather deafening howl.
	"MANBAAAAAAAT!  I WILL FIND YOU AND DEVOUR YOUR BONES!"
The roar of Killer Cat was bone-chilling to the three, the bat himself merely listening out to where the creature laid.
	"He's not in this cavern.  He's probably in his lair nursing his wounds."
	"Hehehe, lickin' 'em like a pussy, hahaha!"
Nobody laughed, and James sneered.
	"Oh fuck you all."

The cavern itself was not natural certainly, hollowed out to make aqueducts that crisscrossed the place with a rather unreliable looking foundation of stone.  Many cracks showed along the entire set of structures, Escher-like in how they went in every direction.
The four began to traverse the cavern, trying their best to climb rock after rock, pillar after pillar with footholds and teamwork.  Manbat easily flew up to each pillar to drop down some ultrafibre rope in case support was needed.  James was a natural, his claws helping to dig into the rock and keep climbing.
Max had the boundless energy and strong feet to keep his hold, while Sam was...a big dog, but he tried earnestly to keep up.  The climbing itself took around half an hour to only get halfway up.  But it seemed to get easier as they went further up on better founded rocks, reinforced from a certain other passageway where one of the waterfalls originated from.
After 15 more minutes, they finally reached near the top of the cavern, only to be troubled by a large gap between two pillars.  Luckily, it could be crossed thanks to Manbat laying down a rope to tightwalk or hang across.  Max tightwalked like a pro, as did Sam strangely who mentioned offhand how they picked up a few tricks in a circus once.  James was not so eager to test his balance and crawled with hands and feet firmly on it, assured by Manbat that his claws could never cut the rope or even damage it.
	"Not even if I did this?"
The raptor joked as he started nomming on the rope, teasingly so without actually touching it.
	"James, stop biting the rope, yer only tempting fate like Ted Kennedy did."
	"Yeah!  That's why ya never show the back of yer head to a book depository!"
	"Max!"
	"What!?!"
	"...I mean the drunk ass Kennedy, not the womanising Kennedy!"
	".......ohhhhh."
Eventually they all got across, and took one more climb to reach the very top of the cavern's aqueducts which was guarded by some elite rat guards, armed with machine guns.

	"HEY, IT'S THEM!"
	"TAKE ÉM DOWN!"
Manbat immediately swung out something towards the guards and one of them suddenly got knocked over the edge and went hurtling into the abyss screaming, before the bat grabbed the item in his claw.  It appeared to be a tiny little silver symbol of a bat.
	"Batarang," he explained.
Sam fired a shot of his magnum to blast the machine gun out of the bewildered guard's hands, who merely stood there shaken.
	"OH GOD, I DUN WANNA FALL!"
	"No?"
James walked right up to the rat and punched him across the head before holding him over the abyss, the rat squealing in his grip.
	"AGH, HELP ME!"
	"Where's the Joke Rat!?"
	"Ah...I-i-i-i dunno!"
	"I think you're lyiiiiing...and my grip gets slippery when people lie."
	"OKAY OKAY HE'S IN THE CONTROL ROOM!"
	"Good."
	"B-but you need a code to get inside."
	"Alright, what is it?"
	"Ah...h-he said, what is the colour of-"
	"ANSWERS, NOW!"
	"ZERO ZERO EIGHT ZERO ZERO ZERO!"
	"Thaaaaank you!"
	"Wait," said Manbat cautiously.  "Put him down."
James shrugged and did so, the rat crawling to the bat and whimpering eagerly:
	"Oh thank you thank you thank yo-"
He was quickly silenced by a slam of a wing into the ground, knocking him unconscious 
	"Well, I guess he wasn't any use to ya right?" said James.
	"I never kill."
	"...really?"
	"Never."
	"And that guy you...bataranged off the ledge?"
	"There's water below us.  All rats are good swimmers, he'll be fine."
	"...whatever floats your boat."
	"HAH, hey that was funny, kid!"
Sam pointed approvingly at James, slightly confused and then realising his turn of phrase.  He chuckled a little in turn, before they stopped messing about and went to the control room ahead.

The control room was situated at the end of a brick corridor, making James remember the time he had been in an abandoned underground railway in London with a few friends.  The slight nostalgia of the cool air made him a little misty-eyed as they reached their destination.  The place was built in an octagonal shape.  Eight niches and four pillars, a rather grand looking sanctum for a sewer's control room.
Each niche had a control panel in it, some for the sewers themselves with screens showing camera views of such, and others showed a rather large pile of minerals of a greenish-red nature.  To their surprise, a rather stately stern-faced human male in his late 60s with a fine suit, stood in the middle of the room.  Sam pointed him out with an audacious cry of:
	"Holy Kriss-Kross on an add-on of a failed home console, Manbat, it's the mayor of Chicago!"
	"Hmm?"
The human turned around and looked at the four animals with slight surprise.
	"Who the hell are you?"
	"Sam and Max, Freelance Police, and-"
	"YOU!"
	"It's been a while Mayor," replied Manbat.
	"I knew you'd turn up eventually, the way Joke Rat goes on about you like you had a thing together."
	"HAH, I said the same thing!" said James, much to Manbat's glare that shut him up.
	"Mayor, we know about the Daleynium supply you have under this island, so don't try to deny it.  I have the evidence of this scanned and filed away."
	"When didya do that?" asked Max.
	"When you weren't paying attention."
	"Oh."
	"So you found out about my newly-discovered mineral," said Mayor Daley, arms spread wide in a corporate gesture.  "Big deal, the plan's going through anyway!"
	"What plan, Mayor?  Surely you're not as insane as Joke Rat, who would use your mineral supplies to blow up entire cities."
	"Not an entire city...just this island."
	"...what?"
	"You have any idea how much this goddamn island has pissed me off!?!  Always they had their fun about their li'l airport strip, and I wanted to be all generous with a park, but no they said, NOOO you can't, so I destroy the entire airport and-"
	"Mayor, we know about what you did with Meigs Field."
	"And the hired truck scandal," chipped in Max.
	"And the leasing of the city's infrastructure," added Sam.
	"Shut up, all of you!"
Daley brought out a small black revolver, a Smith & Wesson 45 which he aimed at Manbat.
	"You wanna know why I want this island gone?!"
	"...because you're mad?" asked James gently.
	"NO!  Because if I don't, Joke Rat'll blow up the entire city of Chicago!  He wants something to blow up and he wants this damn island for some reason!"
	"I knew you'd spill the beans eventually!" said a familiar whimsical voice from above.
Something soon landed on Daley's head perfectly, patting the forehead with little white paws.  Manbat did not even need to say the name for his allies to realise who it was.

	"Joke Rat."
The rat was rather insane looking, his snout streamlined with lipstick from one cheek to the other.  His face was pancake-white with greasepaint, and his fur entirely painted green all while wearing an immaculate purple pinstripe suit.
	"Maaaanbaaaat, how delightful to see you again!  I missed youuuu."
	"Why do you want this island blown up?"
	"Ohhhh haven't you heard?  My fellow rats have had their migration routes ruined by oh, all SORTS of things, and this island is a major obstacle in their yearly migration-"
	"Don't play with me, this isn't about looking after your fellow species.  You never care about anyone other than yourself."
	"...oooohoohoohoohoo, you're too good for meeee...well what can I say?  I wanted to have a bang!  HAHAHAHAHAAHAHAHAA!"
	"Is...he actually insane?" asked James.
	"WHAT WAS THAT!?!"
Joke Rat's tone turned suddenly furious, making James backpedal with:
	"Hey hey hey I know nothing about what's going on here, I just-"
	"REPROBATES LIKE YOU ARE THE ONES WHO RUIN THE GREAT GENIUSES OF THIS WORLD BY CALLING THEM INSANE!  They called Galileo insane for seeing the stars for what they were!  They called Leonardo Da Vinci insane for...well a lot of things, hhhhahahaha, and....me?  Well, I don't know what I can be called insane for yeeeet...but it won't be heard from you."
James shut up and looked away, rather scared by this unpredictable character.  During this distraction however, Manbat had pulled out his batarang and swung it at Daley's hand, slicing a finger to make him drop the gun.
	"AGH shit my hand!"
Joke Rat immediately jumped down to grab the gun as good as he could, the gun being a little smaller than his own body so he could barely hold it up.
	"Ah ah aaaaah.  That was very naughty of you Manbat to hurt the mayor, you might go to jail for assaulting a public official!  Besides, my good buddy and I are going to make sure this island will go to hell...and then I might try Chicago."
	"WH-WHAT!?!?  BUT YOU SAID-"
	"Ohhhh please, did you really think you could trust a rat!?!  God you are stupid."
Joke Rat then brought out his own gun, a small Magnum that was tailor-made for his pint-sized self.  He shot the mayor in the shoulder with a dart, who grunted and then collapsed in a few seconds.
	"MAYOR!" cried out Manbat.
	"Ohhh relax, he's just a little sleepy."
The rodent then reloaded with another kind of ammo instead of tranquiliser.  Bullets.
	"Let's dance, Bats."
Joke Rat immediately began to strafe and shoot, making the four run in their separate directions in the room.

	"HAAAAAAHAHAHAHHAHAHAHAHAA, what's wrong!?!?  You feelin' a lil shot down!?!?"
The psychotic rat blasted his magnum through rocky pillars at his opponents, the four of them trying to make their own strategies.  Manbat was only aiming to take him down, a sneak attack from the air as was his way.  But he soon found himself impeded by an electric net halfway up the ceiling, not high enough out of Joke Rat's view.  Eventually he signalled to the three to regroup in a suitable cover spot under the shadows.
	"If we want to take down Joke Rat," began Manbat when they regrouped, "we need to destroy the net so I can get to him."
	"How do ya plan to do that?" asked Sam.
	"All four of us have to work together to undo the net simultaneously.  First we agree on which part to take down.  I'll take down the northwest corner because it's in the darkest area."
	"Righto."
Sam looked up at the three remaining corners and noting their positions as well as the different knots they seemed to employ.
	"I'll take that one opposite yers, it's got a knot I can undo easy."
	"I knew yer scout training would come through Sam!"
They all duck at a bullet that came too close to their heads.
	"Max, you take out that one there."
He pointed at the southeast corner which was rigged securely to an iron pipe.
	"James, you handle the last one."
	"Okay, how do I deal with that?"
He looked over at the southwest corner, fastened with a special knot that not even Sam recognised.
	"Any way ya want kid."
	"Now, everyone ready?"
Manbat's question was eventually replied to with three nods as they ran off into their directions, the Joke Rat slightly confused before he giggled to himself.
	"Ohhhh I see, it's all about teamwork!  Ohhh I should have known the most unlikely group of characters would eventually unite against the common foe.  But oh well, might as well make my mark on oooooooooh....YOU!"
He fired in Max's direction who easily dodged the bullet with his hyperactive senses, the Joke Rat not giving up on trying to hit him before Max began to tear at the rope from the window frame, or try to.
	"SAM!  I CAN'T!  THE ROPE'S TOO TIGHT!"
	"MAX, THINK ABOUT THE WORKS OF LARS VON TRIER!"
	"...nnnnnnggghhhhh-"
	"A-AND HE'S TELLING YOU ABOUT THEM IN A 2 HOUR SPECIAL OF INSIDE THE ACTOR'S STUDIO!"
	"...NNNNNNAAAAAAAAAAGH!"  The furious rage that suddenly awoke in the rabbit did enough to tear off the rope from the frame, as Sam undid his rope end with the knot.  Manbat easily detached his target with his sonar aiding him, while James was frustrated at being unable to undo his.
	"...oh fuck this."
Eventually he just pulled out his G18 and fired insanely at the cluster of knots with both hands keeping the gun steady, bullets sparking in front of him like welding sparks before it eventually cut free.  The net landed on the floor, still electrified but now no longer above them, leaving Manbat free to attack.
	"AH!  So you did undo the net, well done!  Even if one of you did break the no-shooting rule."
	"FUCK YOU, I CAN'T DO KNOTS!"

He aimed at Joke Rat with a wild stream of bullets which the rat dodged simply by rolling to one side and behind a pillar, but it gave enough a distraction for Manbat to swoop in and scrape at his foe's face with his claws.  Makeup tore off in strips as he clouted Joke Rat with his strong wings, a hefty smack sounding out against the stone column.
	"Show's over, Joke Rat."
	"Ngh hehe...hahaha, but the people LOVE me, Manbat!"
	"Can't have too much of a good thing."
Another hard whack in the head with both wings rendered him unconscious, as the still-smiling rodent was out.  The detective duo and the raptor came closer to investigate.
	"So is that crazy fuck out yet?" asked James.
	"Seems so, I'll keep him here and report to the authorities."
	"Well, looks like another mystery solved!" said Sam with his hands clapping in resolution as Manbat replied:
	"Not quite.  There's still the mystery of who let the criminals out.  Evidence points to Daley."
	"Why would the mayor of Chicago wanna do a crazy thing like that!?!?"
	"Coercion from Joke Rat, must have found out somehow about the Daleynium and threatened to use it, pick the lesser of two evils."
	"Yanno," began Sam, "I expected a plan far more elaborate and maniacal from someone like this guy."
	"You read too many comics."
	"AH AH AAAAAH!"
Joke Rat suddenly opened his eyes, surprising every one of them as he pressed a button hidden in his suit, which soon began a large shuddering from downstairs.
	"Wh-WHAT WAS THAT!?!?!" cried out James who would soon be answered with:
	"WARNING.  DALEYNIUM HAS BECOME UNSTABLE DUE TO VOLATILE PROXIMITY.  ALL RESEARCHERS PLEASE INVESTIGATE AND DEFUSE THE SITUATION.  ALL OTHER STAFF, PLEASE EVACUATE OFF OF THE ISLAND."
	"Oh GOD DAMMIT, NOT ANOTHER SELF-DESTRUCT!"
	"Wha?!"
Sam was a little confused but James just ran shouting:
	"IT DOESN'T MATTER, LET'S GET THE FUCK OUT OF HERE!"
They all agreed and immediately ran as fast as they could, with Joke Rat slipping away from their grasp and running to another unseen direction.  Manbat did not waste anytime in escaping with his allies.
	"Wow, he sure was crazy!" shouted Sam, "Crazy enough to blow up this entire island!"
	"With that much Daleynium he might even blow up the city itself," said the bat, "we have to disarm it!"
	"WHAT!?!?"
All three said the same thing, with James shouting:
	"NO FUCKING WAY AM I GOING NEAR THAT PILE OF ROCKS!"
	"We're the closest ones to it, if we can't somehow defuse the Daleynium, then millions will die."
	"But what if we can't!?!?"
	"Then we die like everyone else.  You'll never be able to outrun the blast anyway."
	"THE FUCK I CAN!"
	"...We're going with you!" said Sam dilligently to Manbat.
	"Oh you got to be SHITTING ME!"
	"James, he's right, if nobody else tries it then all is lost!"
	"Yeah, you gotta believe in yerself!" said Max cheerfully.
	"I...I can't do it!"
	"Yer coming with us!"
	"...GODDAMMIT!  Fine!  Let's do it!"

Finally running all the way to the far back of the sewers where the natural cavern full of rumbling Daleynium laid like a pile of explosive jellybeans, Manbat did his best in scanning and figuring out a way to defuse them.
	"How the fuck can we stabilise minerals?!" asked James in a panicky way.
	"Various temperatures of water."
	"...wait what?"
	"Studying their igneo-sedimentary compounds, they're packed with explosive chemicals from volcanic effluents with properties similar to nitrocellulose."
	"...so...they come from volcanoes, and the explosive stuff in volcanoes that makes it go boom is actually trapped inside?"
	"Exactly."
	"...jeez you know a lot of shit."
	"We need to get water on them, fast."
	"Well we ARE in a sewer, we just need some buckets."
	"How long we got?"
	"Twenty minutes at the most, we need a specific temperature as well, around 102 degrees fahrenheit."
	"...isn't that the body temperature of a rabbit?" said Sam, to which Manbat could not dignify that with an answer.  "No no wait, what if MAX got all the water in his stomach, and came back here and hoiked it all up?"
	"Aww goddamnit that's gross, seriously?!" said James in disgust, but Manbat stood up and said:
	"Do it."
To Sam's surprise, they went with this plan and Max became excited.
	"OH BOY!  I can retain water!  I always wanted to be a mommy!"
	"You were already one, remember John?"
	"I can be a mommy agaiiiiiin!"
Max giggled a little insanely as always before they rushed to the nearest waterfall, all across the aqueduct bridge.  Thankfully it was a clean one, as Max began to use his amazing stomach-based powers to swallow as much water as he possibly could.  James sat around doing nothing and trying to figure out what 102 degrees fahrenheit was in celsius, to keep off the thought of impending obliteration.

The first vomiting volley of water from Max did nothing to defuse the situation, literally, and panic rose.  Manbat encouraged them to try again, and so Sam and Max went back along the path to bring up another volley of water, warmed by Max's innards and once again hurling it onto the rocks.  Nothing, but there had been a slight change.
	"Keep going, we almost have it."
Despite their masked vigilante friend being extremely calm with the situation, James was panicking and unable to cope.
	"I...I can't take this!  We're gonna blow the fuck up because of some stupid rocks, how can you be so calm about it!?!?!"
	"Because running around scared will be even more useless."
	"GOD...DAMMIT!  THAT'S IT!  I'm leaving!"
	"You can't run fast enough from the blast."
	"I didn't say I was gonna run!"
He sat in a corner far away from the dangerous rockpile, and began to make his most fervent wish in trying to escape.  Begging, wishing, pleading to himself to get out of here, thinking of something, anything to do so.
	"Hey James, I didn't know you were religious!" said Sam as he rushed back with Max ready to puke up more water.
	"Shut up, I'm trying to think!"
	"Ya better hurry, cuz if Max don't do this right we'll all be worm food!"
	"NNNNGAH!"
Focusing all of his will, James began to feel something click in his head.  Not wanting to be worm food.  He soon felt the familiar embrace of the dimensional abyss.
Manbat turned to look at the raptor, while Max just vomited water once again on the pile of rocks.  The corner where the raptor sat started to bend slightly into itself, a howling abyss slowly devouring him into a small tear of reality coloured black and blue.  Soon he disappeared, the howling fading away, and the three looking at each other rather confused before Max realised something.
	"Hey!  The alert's stopped!"
	"W-wait, we defused the rocks!?"
	"Appears we have.  Good work detective."
Manbat offered his clawed wing to shake and Sam did so politely.
	"The pleasure's all mine, Mr. Manbat."
	"So...where'd that kid go, Sam?"
	"No idea Max.  But I guess we ended up solving one case while gettin' busy with another that'll never be solved."
	"Just like Iraq."
	"Hahaha, you crack me up li'l buddy!"