Episode 4 starts off with Farnsworth forgetting what he was going to tell everyone, before getting a message from Cubert, saying he forgot to pick him up. After forgetting about leaving the bath on, Farnsworth is diagnosed with Absent-minded Scientist Syndrome. Amy then looks up something about a study involving lab rats and memory, which turns out to be from Farnsworth. He then remembers that he did research on Vivisectoid Alpha, where he put rats in a difficult maze to enhance brain chemistry, and extract their cerebral fluid to treat absentmindedness.
The crew then head to the planetoid to investigate, but find nothing but an asteroid field, which causes them to crash somewhere. They eventually discover that they are actually on a ring-shaped planet, and run into Dr. Vermius, a big, smart rat, who will bring them to Rathatten in the morning. Around the fire, Farnsworth explains that the rat is a descendant of his lab rats, larger brain power demands larger body size, and they have to keep it a secret why they’re there.
After a tour of Rathatten, the crew is brought to Ratcliffe University, where they are told how the ring world was made, and that Dr. Vermius is plotting his revenge against the “Evil One” who left them in the maze. After being given the laboratory to sleep in, Farnsworth recognizes a piece of technology as his old orbiting security drone, which may have recordings of the planet. Farnsworth then plugs bender into it, and the video reveals that the planet exploded, likely from a pressure buildup in the cheese cave. The heat blast then melted the rocks into a solid surface, meaning the rats didn’t build the ring, but infested it. Dr Vermius then bursts in, saying he knows Farnworth’s the evil one, and traps them everyone in a maze to experiment on them.
After tests have concluded, Vermius lets everyone know of the disease that’s going around, and Vermius then tells the crew that they will be dissected to study their brains in the morning. Dr. Pestia lets everyone out and says that everyone is suffering from humonic plague. She gives the crew a part to fix their ship, but Farnsworth stays behind to try and help cure the disease.
While Farnworth is infected with the disease to try different cures, the rest of the crew run away from the rat patrol, but eventually get surrounded, with the ship on the other side of the ring. Bender then tells everyone to jump when he says to, and kicks the ring, causing it to flip, and allowing them to get right to their ship. The crew then get the ship working, but end up crashing again.
With everyone suffering from the plague, everyone realizes that Fry is completely fine. This is because he has on the makeup from the trials, which formed a protective shield, and also put Arsenic in his bloodstream, killing the fleas that spread the disease. Everyone is then cured, and the maze trial seemingly helped Farnsworth’s brain, meaning he no longer needs the brain fluid, so the crew head off.
This was another one of those silly, good episodes with all the little things, like how they cured the humonic plague. It also had moments that were a quick chuckle like Bender throwing a rock at Fry’s face to test the gravity, even though he knew what would happen. Was it the best episode so far, hard to say, but it definitely was still a good episode.
Rating: 7.5/10