Zoidberg heroically spreads goodwill throughout the universe while traveling through time and space in a Port-A-Potty, righting wrongs and restoring order, which begs the question: is the good doctor in the correct sci-fi series this month?
The Professor has built the world's greatest porta potty. It is small on the outside but very large on the inside (everyone can fit inside). When the toilet is flushed, the porta potty randomly teleports to someplace in space and time. As the Professor demonstrates, they appear near a ship on the edge of a Black Hole. The crew of that ship begins to panic and a little gray and red floating robot accidentally sends them into the black hole when trying to take evasive maneuvers. If the porta potty is flushed again, it returns to where you started because the coordinates for the present day Planet Express are pre-programmed into it.
The Professor leaves for an interview with Straight Poop magazine. Hermes comes in and starts giving Zoidberg a hard time. When Fry asks him when he's going to let up, Hermes tells him it's just his management plan of breaking his spirit then building it back up. Zoidberg goes inside the potty and dreams how he could decorate the large room. The others join him telling him he shouldn't be messing around inside. Zoidberg says he's a doctor and knows what he's doing. With this, he leans on the handle and accidentally flushes the toilet. They appear in a sea of holes (with a yellow submarine in the far distance).
Fry finds some crystals in the urinal but Leela scolds him to put them back. Suddenly an image of the Professor appears. The Professor made the operating program in his image. It tells them that the flush return mechanism broke when Zoidberg leaned on it. Unless they know the exact coordinates of the space and time they came from, it will be pretty hard to return. Fry suggests they just keep flushing in the hopes of eventually getting back home.
They arrive in what appears to be an olden age on Earth. A man in rags pleads for their help. His village has been wiped out by goblins and trolls and dragons breathe fire on everyone. Bender tries making it so they can't help but Leela is quick to help out. The man takes them to a room full of nerds playing on computers. It turns out, the battle is on the computers. They are playing World of Battlecraft and haven't eaten or slept in days. They can't seem to stop themselves from playing. Zoidberg thinks it's great that they are all playing together and bonding but then he accidentally trips over the plug. All the computers shut down. People then begin to remember that they had actual lives before playing. Zoidberg prepares to apologize but the people are happy. They decide to throw a feast in his honor. Leela grabs him before it starts. As they are about to leave, Zoidberg is given a medal with his name on it.
Now the crew find themselves on a candy planet. A bunch of birds (going coo-coo over cocoa) are being forced to do slave work for an evil dictator, the Lord Candyman. As soon as Fry steps out, he begins eating a hunk of chocolate. He is warned not to eat it. Fry is now worried that it might be a chocolate laxative (like he accidentally took once in high school) but is told that it all belongs to their evil dictator. Zoidberg comes along and tells Fry he should taste a piece of a licorice man that he found. Everyone stares at him. Zoidberg is a hero once again. He receives another medal with his name on it.
The next planet they arrive is full of robots. It is ruled by the Deacons (that look suspiciously like Daleks). When Bender says something they consider blasphemy, they begin to try to "Excommunicate" them. Their only escape is to run up some stairs. The Deacons wonder why they bothered building them. Zoidberg is cowering behind the porta potty. When he is asked what religion he is, Zoidberg gets so nervous that he squirts out ink at them. The Deacons cannot see and try to simply feel around for him. Then they become stuck when their "holy suction cups" get stuck. Now that the world is freed from their tyranny, the robot populace hails Zoidberg as their hero. He is given yet another medal.
Fry and Leela wonder how they will get back when Bender arrives with good news. The porta potty's CPU is female so he was able to romance the coordinates out of her to return home. When Zoidberg hears that they have the coordinates to return home, he decides to input them incorrectly so that he doesn't have to return to his normal unheroic life.
Upon arriving on Earth, things seem a little different. Leela's "wristamajig" tells her that they have arrived twenty-five years into the future. Fry is excited because he's always wanted to live in the future. A robot comes along and takes them into custody because humans do not have the right to speak. Zoidberg approaches one and assumes his luck will strike and he will save the day again. Instead of his luck, a robot strikes him over the head. They are brought to the ruler of Earth, the prime president, Leelan Von Fry-Bot. He tells them that Fry and Leela are his mom and dad. Being half human and half mutant made him face discrimination and predjudice. He decided to take Bender apart and use his steel body to replace his weak flesh organs. He then became strong enough to take over the world.
They are all placed in a permanent time out. Fry is happy because this means that he and Leela eventually...Leela smacks him before he can finish his thought. Fry, Leela, and Bender decide they cannot fight their offspring when Zoidberg talks about taking him down. He gets Bender to bend the prison bars and escapes on his own. He plans on taking down Leelan himself but realizes that he's too much of a coward. He eventually finds his older self and discovers the truth. Zoidberg had returned on his own to the present. The Professor was saddened and planned on making a clone. He only had enough genetic material to make one clone so he combined the two. Bender's backup memories were uploaded into another bending unit and served as a nanny for the baby. Bender's lullabies about destroying humans were the inspiration Leelan used to take over the world. The old Zoidberg pleads with his younger self not to make the same mistakes he made.
Zoidberg manages to trick Leelan into getting captured. The others are freed and return to their present. Fry steps out ready to tell the Professor and Hermes how Zoidberg actually saved them. Before he can say a word, the Professor sprays them with a "lilac-scented short term memory eraser" so that their memories won't damage space and time (and allow them to cheat at the Lotto). With things pretty much back to normal, the Professor wants DNA samples of Leela and Fry and Bender to backup his memory. He says that the business can't afford to miss a day's delivery if this were to happen again. The Professor doesn't want Zoidberg's DNA and Hermes yells at him to get to work. Bender finds Zoidberg's medals inside of him. Knowing that this must mean that he actually did something heroic on their trip, he figures there's only one thing to do. He crosses out Zoidberg's name and writes his own and shows them off to the others.