Negaduck and the Fearsome Five are dividing up the loot from their past caper. Negaduck is trying to leave and the others keep asking him where he is going and that they want to go to his secret hideout too. Negaduck tells them that he wants nothing to do with them and leaves. Quackerjack suggests they follow him to find out where his secret hideout is.
Meanwhile, Gosalyn insists that Drake goes to Honker Muddlefoot's birthday party even though he does not like the Muddlefoots. Launchpad is picking up the cake and misses the fact that Negaduck walks past him, but as he is leaving he sees the other villains walk by and knows that he needs to tell Darkwing.
At the party, Drake is dreading the party as Herb uses a theme based on Pelican's Island for Honker's birthday. Launchpad brings in the cake and gets out "Fearsome" before passing out. Drake finds out, after Launchpad recovers, that the Fearsome Five is at the bakery. Drake causes Tank to accidentally fall into the cake and uses the excuse to go to the bakery as Darkwing Duck.
Back at the bakery, the other villains walk in on Negaduck as he is peering into a giant cake. Just then Darkwing shows up and Negaduck is furious at the fact that they led Darkwing to his secret hideout. They jump Darkwing and throw him into the cake. Negaduck is really mad now. This is his real secret hideout, the Negaverse. They run away when they see how made he is and Negaduck jumps in after Darkwing.
Darkwing lands in the Negaverse and sees St. Canard is dark and dirty. He gets to the house and things are a wreck. Nega-Gosalyn comes in the kitchen all dressed up wearing a pink dress where Darkwing is and tells him that she has dirtied up the kitchen as he asked. Nega-Launchpad then comes in and complains that someone had planted a rose bush and he chops it with an ax. The television comes on and Negaduck appears and tells everyone that Darkwing Duck is loose in the city and to arrest him and tells everyone that Darkwing looks just like him. Nega-Launchpad recognizes that Darkwing is right in front of him and tries to blow him up. Darkwing grabs Nega-Gosalyn and runs out. They run next door to the Muddlefoots and run into Nega-Tank. Nega-Tank is polite and smart and tells Darkwing that he is in the Negaverse and tells him that everything is opposite in this universe from Darkwing's. Nega-Herb and Nega-Binkie show up and take Darkwing to meet Nega-Honker for his birthday party thinking that Darkwing is Negaduck. Nega-Honker recognizes who Darkwing is and they grab him and start to put him over a giant grill. Darkwing gets shocked and blacks out.
Darkwing wakes up with Nega-Megavolt, Nega-Liquidator, Nega-Quackerjack, and Nega-Bushroot jumping for joy that they got Darkwing Duck. Darkwing learns that they are the Friendly Four and that they are against Negaduck. They tell him they rescued him. Darkwing thinks it's a dream at first and hits his head against the wall. He then realizes that he is actually in the Negaverse. He wants to get back to his own universe, but when he sees Nega-Gosalyn, he knows that he must stay and fight Negaduck.
Darkwing starts training the Friendly Four when Negaduck bursts in with the Nega-Muddlefoots and Nega-Launchpad. He has everyone taken to "the tower". He imprisons the Friendly Four, Nega-Gosalyn, and Nega-Tank in a glass cylinder and has Darkwing under a giant hammer that will squash him once the blade that is swinging cuts through the rope holding the hammer. Negaduck leaves to create more mayhem. The Friendly Four begin to berate themselves as the blade cuts the rope. Quackerjack produces one of his toys and Darkwing tells him to use it. The clown breaks the glass and frees Darkwing just in the nick of time. Darkwing tells them it's time to fight Negaduck.
The Friendly Four begins to clean up things and make it right. Negaduck sees all of this and starts to go to Darkwing's universe to wreck havoc there. The Friendly Four show up at the bakery to stop him. Negaduck tells Nega-Herb to eliminate them. Nega-Megavolt tells the Friendly Four that they will prove that they are not losers anymore and they knock Nega-Herb into the others. Negaduck jumps on Darkwing and they roll into the room with the portal. Negaduck knocks Darkwing into the Friendly Four and jumps into the cake. Darkwing starts to chase him and asks Nega-Gosalyn what will she do. She tells him not to worry and that the Friendly Four are there to take care of her. Darkwing jumps in after Negaduck.
Darkwing catches up to Negaduck just before the portal to Darkwing's world. They fight again. Darkwing accidentally pulls the universal plug and Negaduck gets pulled in and Darkwing barely manages to get to his universe. Darkwing returns to the party with a new appreciation of how things are in his universe.