St. Canard is a bustling city, but unfortunately for its population, activity barely diminishes way below the streets. A fair variation of the city's criminal population has made its home in the sewers and the caverns, biding their time until a new plan is ready to be set in motion. A good reason to live in the St. Canard undergrounds is that it is quiet and far removed from the police forces, but for many, odd as it may seem, it's the living conditions that are the selling point.
There's an entire community of mole people, which is led by Professor Moliarty, living under St. Canard. The surface is not fit for them due to daylight hurting their eyes, meaning that if they venture aboveground, it's only at night. They have their habitat in spacious caverns, which seem to be part natural formation, part dug out to fit their needs. They share the burrows with giant pill bugs and giant slugs, which are their pets. The slugs are kept in separate pits to occasionally be fed an intruder, while the pill bugs are allowed to roam freely, probably as security setup. Though the moles don't need more space, they do every so often expand the burrows to fit the designs of Moliarty's schemes. Access to and from the burrows is limited to what the moles create, but since they aren't very strict with closing up the holes they make, it's not a big limitation.
The caverns are located in the middle of the sewer network. They do not appear on the map of the sewers and all access from the tunnels is boarded up. The only way in or out without breaking anything is through the ice factory belonging to Isis Vanderchill right above. Needless to say, the caverns are Vanderchill's hideout. They are the only place in St. Canard warm enough for her to live normally. The caverns, which are filled with lava pools, appear a natural formation, but if so, Vanderchill has had some work done on it. There are buttons everywhere to control the lava, flames, and even deposits of snow. There are also an elevator and stairs, which provide the aforementioned sole access to and from the caverns.
There's at least one area in the sewers with several large drains, which Darkwing figures are water treatment systems. Jambalaya Jake and Gumbo have built themselves a house in the middle of one such area. They chose the sewers because it is the closest the city has to offer to the bayou they come from. With the drains around them and several switches, levers, and wheels near their hideout, they essentially have a home security system built for them by the good people of St. Canard. Jake has improved it with a few traps of his own for just that little extra of keeping people out. Though he usually uses the walkways or rides on Gumbo, Jake does have a rowboat present at his hideout.
Macawber Mushrooms Unlimited
In addition to Macawber Manor, Macawber Mushrooms Unlimited also takes up room in the sewers underneath. There are direct pathways leading between the two areas so that the staff, Morgana Macawber and her associates, can travel out of sunlight and away from prying eyes. The sewer portion is used as the mushroom farm and it is there the stolen loot for the experiments is brought. Macawber Mushrooms Unlimited aims to create a mushroom that tastes exactly like pizza and so most of their crop smells like pizza. The mushrooms are kept in cages because the experiments also made them mobile and omnivorous. It appears Macawber Mushrooms Unlimited was ended after Morgana aided Darkwing and her associates and crop were killed, but if everything was cleaned up or not is unknown.
Quackerjack has a few hideouts, but by far the most extraordinaire is his toy kingdom. It's a large room located in the sewers where Quackerjack has situated his current toy factory, along with a makeshift throne. The available space is used for three purposes: firstly to store the production machinery, secondly to house a "city" of buildings made from oversized building blocks, and thirdly to stash piles and piles of all kinds of toys. Needless to say, Quackerjack is proud of the place. When Darkwing destroyed it, Quackerjack was devastated enough that instead of rebuilding it he intended to blow up the place. Darkwing prevented this, but it's unknown what happened to the kingdom after that event.
Professor Moliarty has made himself leader of the mole population living in the burrows under St. Canard and has them and their truck-sized pill bugs steal several structures and other resources from the surface. His plan is to create a Kineto Beam that will put the moon in front of the sun above the United States of America, thereby establishing a surface environment suitable for his people to conquer and live in. The large holes left where buildings once stood draws the attention of Darkwing Duck and Launchpad, who descend into the burrows. They witness Moliarty steal a baseball stadium with an elevator built underneath, but Darkwing blocks the mechanism with a rock before the stadium comes down completely. Moliarty demonstrates the machine isn't hindered in the slightest by the rock and his troops surround the two heroes. Unbeknownst to all, Gosalyn and Honker have traveled down with the stadium. The two children at first cause Darkwing and Launchpad to be captured, leading to them being brought to the slug pits to serve as slug food. Gosalyn and Honker make up for it by taking out the guards and saving them from the slugs, after which the quartet quickly locates an elevator to take on Moliarty and his troops on the surface. Morgana Macawber and the board of directors of Macawber Mushrooms Unlimited have the portion of their farm where they breed mushrooms that taste like pizza set up inside the sewers. When Granny and her pet snake fail to kill Darkwing and Launchpad, they flee into the sewers and the heroes follow them. This way, they find the farm. Believing he can take on the four directors and vengeful because he believes they're operating behind Morgana's back, Darkwing shows himself. He and Launchpad immediately get chained up. Morgana joins the scene and reveals she's just as much part of the secret pizza-mushroom farm as the other four. The other four want the heroes dead, however, which is something she does not agree with. She proposes to make Darkwing join them with enchanting lipstick instead and have him feed his sidekick to the mushrooms. This gets approved, but Morgana switches the lipstick for a harmless version. Darkwing plays along until he gets an opening to temporarily incapacitate the directors and he, Launchpad, and Morgana can make a run for it. They rush up to Macawber Manor, while down in the sewers the directors vote Morgana out of power and sic the mushrooms after their prey.
Jambalaya Jake and his alligator Gumbo move from the bayou to the sewers of St. Canard to have easy access to the city's riches. They find Darkwing in their way, who due to the smell hanging around Jake deduces he's hiding in the sewers. He and Launchpad go there when the time comes to confront the crook. Darkwing gets caught in a beartrap and Launchpad finds himself hunted by Gumbo before Jake shows himself. He challenges Darkwing to wrestling at a waterfall-drainage structure, which he loses. Darkwing plants one of the brownie's he's found Gumbo to be fond of in Jake's pants and calls the alligator over. As Jake tries to outrun his pet, they both fall down the waterfall and are flushed through the whirlpool below. They survive and promise to return another day. Out for revenge, Jambalaya Jake plans to gain mind control over Darkwing, but gets a hold on Launchpad dressed up as Darkwing instead. Because Launchpad is strong and looks enough like Darkwing to fool people, Jake keeps him to pull heists for him and help carry his shoppings back to his sewer home. Darkwing figures out what is happening and tracks them to the hideout. Jake sics Gumbo on him, who knocks Darkwing into the water. Jake turns a nearby wheel, washing Darkwing away to a large drainage. Launchpad follows and would've thrown him in if not for Jake calling him back to finish the job himself. Sheer luck for Darkwing has Granny Whammy, who sold Jake the mind control powder and is still waiting for payment, show up and free Launchpad to teach her grandson a lesson. Jake and Gumbo make a run and swim for it, but Darkwing and Launchpad block a tunnel entrance each, cornering the villains. Darkwing takes them out with a special kick, then dresses them up in his and Launchpad's Darkwing outfits to clear his name when the police comes over to arrest them.
Moliarty has his sights set on a machine to blow away the surface-dwellers. A spider mutated to people-size proves easily manipulated to serve him, which comes in handy during confrontations with Darkwing Duck both aboveground and belowground. Darkwing is bitten by the spider, causing him to grow four more arms and spit cobweb. While useful for the time being, it is a condition that needs to be cured. Launchpad, Honker, and Gosalyn enter the sewers to search for a similar spider to create an antidote. They do find such a spider, but lose it again while searching for Darkwing. Megavolt gets slammed out of the window and falls several stories down into a manhole, below which the sewer water disagrees with his charge. Once Bud Flood has gotten comfortable in his new body and taken up the name Liquidator, he creates a hideout of sorts in the sewers. When he spots Darkwing driving past, he breaks through a fire hydrant and grabs him to take revenge. He leaves Darkwing to recover at a makeshift stage area, where he and his mascots make a show of presenting the new and improved water salesman. Once Darkwing realizes who and what he's up against, the Liquidator imprisons him in a column of boiling water. Darkwing would've met his end there if it wasn't for the arrival of Launchpad, who has come to look for him after his abduction. The Liquidator is taken offguard and flees up a pipe into the St. Canard Water Works. Through and through, the heroes follow the watery villain back to his factory and then find the tables turned on them. They have to flee back into the sewers to escape drowning. As they run for it, they come across a plumbing component Darkwing lost two days prior. This means they're under 537 Avian Way and can safely go up, which the immediately do to escape Liquidator's attack.
Darkwing Duck and Launchpad lock themselves in with a supply of gold to guard. They witness a hole being burned in the ground, from which a swarm of firebugs emerges that proceeds to melt the gold. The gold subsequently flows through the hole into the sewers. The two heroes make a bigger hole for themselves to go through and follow the trail of gold left by the firebugs. They are spotted by a scout, however, who takes a shortcut and reports on their presence. The firebugs leave their pot of gold and proceed to attack. Darkwing defends himself with a pipe, but they melt it right out of his hands. Next, they make a hole in the celing, dropping the inner piece on the heroes and then going through to make a huge snowball outside. They dump the snowball through the whole, which chases after the heroes until the enter a tunnel with a boarded up end. They grappling-hook themselves up to the ceiling, making the snowball pass them and break the barrier. On the other side, they discover the caverns and meet Isis Vanderchill, who is immediately smitten with Darkwing. He and Launchpad try to make a run for it, but Vanderchill stops them with several traps. After telling her story, she offers to help Darkwing find the firebugs he's looking for, which he warily accepts. She takes him up in the elevator, separating him from Launchpad, who later makes his way back to the surface by means of the stairs. Steelbeak and his Eggmen hide in the sewers when Darkwing barges into their hideout. As he leaves, Steelbeak conceives of the idea to make Darkwing look like a villain so Gizmoduck will keep him occupied. Darkwing needs to get Gryzlikoff off of Herb Muddlefoot's trail and therefore challenges him to jump over a fence. Gryzlikoff takes the bait and jumps right into an open manhole.
Quackerjack has trouble selling his toys because they're lethal. He reasons the problem is the parents, so he plans to get a bunch of children to his toy kingdom to sell his products to. He does manage to convince about six children to come with him, but upon his first sale the flaw in his design becomes visible: children don't have any money. Not to be beaten so easily, Quackerjack improvises that he can put them to work in his factory, pay them, and then have them buy the toys with their salary. Despite the shackles around their ankles, Gosalyn, Honker, and Tank find a way through the sewer tunnels to a manhole. They can't get out because Drake Mallard is standing on top of it, but before the children are dragged back to the toy kingdom by Quackerjack's robot chattering teeth, Gosalyn gets his attention and tells him where they are. Darkwing is subsequently just in time to prevent Quackerjack from executing her. As the home team, Quackerjack dominates the ensuing fight up until Darkwing is knocked into one of the building block constructions and the entire kingdom comes tumbling down. Distraught, Quackerjack aims to blow the ruins up, but Darkwing stops him at the last moment. Launchpad, Gosalyn, Darkwing, Quackerjack, and Megavolt are flushed into the St. Canard waterworks and end up in a whirlpool. Using a combination of Quackerjack's robot teeth and Megavolt's power cord, Darkwing creates a grappling hook to get everyone out. On shore, he finds the wheel controlling the gates and closes them, stopping the whirlpool, but the two villains use the moment to escape in a rubber boat. Darkwing stops them by shooting a toothpick at the boat. Darkwing sends Yucky Duck into the sewers to look for Bushroot, even though he's never had a hideout there. Negaduck flushes Darkwing down a manhole by manipulating the fire hydrants with the magic crystal amulet. He thinks the hero's out of his way for the time being, but Darkwing jumps out of another manhole seconds later. Launchpad and Darkwing take a blindfolded Megavolt to Darkwing Tower through the sewer route. The sewers' waterways don't agree with Megavolt's powers.
After making his way through the city, Darkwing Duck is informed that Liquidator is wreaking havoc in the sewers. He makes his way down and fights through dagger ducks, parachute eggs, hammer eggmen, charging alligators, shadow crows, flamethrower moles, and bomb kangaroos until he reaches the Liquidator's chamber. Liquidator hides in the water, during which time he can not be harmed, but occasionally comes out to play Triton. Forming a horn of water, he either sends water shaped like fish directly at Darkwing or raises bubbles which take the shape of birds as they target Darkwing. He is vulnerable during these attacks and Darkwing uses that to defeat him. / Out to arrest Moliarty, Darkwing descends into the burrows, where he faces eggmen, bats, spiders, reptiles, and giant slugs controlled by eggmen. When finally face to face with Moliarty, the latter's strategy consists of stying underground, where Darwking can't get to him, and occasionally coming up with a bazooka. Darkwing dodges the shots and takes down Moliarty.