The Planet Express crew visits Amy's parents, Leo and Inez, who are destroying the "old" Mars Vegas and constructing a more extravagant one. A group of eco-feminists (calling themselves "eco-feministas") led by Frida Waterfall protest the destruction of the environment, leading to an accident wherein a piece of Frida's jewelry lodges inside Fry's brain. The destruction upsets Leela, but Leo has bribed Professor Farnsworth to rubber stamp the project as environmentally friendly. Leela saves a Martian muck leech, the last of its species, from the site.In New Mars Vegas, Fry starts to go mad when he cannot stop hearing the thoughts of everyone around him. He meets Hutch, a transient who advises Fry to wear a tin foil hat to keep others' thoughts out of his head. Hutch warns Fry never to reveal his powers and to beware the "Dark Ones".While golfing with the crew, Leo reveals plans to build the universe's largest miniature golf course, destroying 12% of the Milky Way in the process. Farnsworth and the crew survey the site and discover an asteroid in a violet dwarf star system teeming with primordial life. Despite this, Farnsworth approves Leoâs project. Disgusted, Leela joins the eco-feminists, who begin sabotaging the project.The asteroid in the violet dwarf system.Hutch introduces Fry to the "Legion of Mad Fellows", a secret society of tin-foil-hat-wearing telepaths led by the Number 9 man. No. 9 tells Fry a story of two species that worked together to survive, until one broke the cycle and caused an "evolutionary arms race", both species evolving to defeat the other. One became the extinct "Encyclopods" who evolved to preserve the DNA of endangered species so they could be restored should they become extinct. The other became the "Dark Ones", who want to destroy all life. Fry learns that the violet dwarf is the only surviving egg of the Encyclopods. Due to a resurgence in the life-giving force "Chi", the Encyclopod will soon be reborn. As Fry is immune to the Dark Ones' psionic powers he alone can save it from Leo Wong's plans to turn it into a golf course, and from the Dark Ones, who have evolved to the point that no one knows what they look like.To end the sabotage, Leo enlists Zapp Brannigan and Kif Kroker, who in turn hire Bender to track down the eco-feministas. Fry infiltrates Leo's empire as a security guard. Amy is angered by her father's sexist jokes and joins Leela, while Bender bugs Fry's phone in case he communicates with Leela. Fry runs into Frida and has her take a message of support to Leela, but an unseen Dark One murders Frida.Farnsworth prepares to close Planet Express; with their delivery team missing they cannot continue. Leo Wong hires them to put up a fence around the construction site. Farnsworth cancels the closing and goes with Zoidberg and Hermes to do the job. They are captured by the eco-feminists, who commandeer the Planet Express ship. When the eco-feministas suspect Fry of murdering Frida, Fry and Leela arrange a rendezvous. They are ambushed by the Nimbus, which was tipped off by Bender. The eco-feministas are sent to prison.At a Legion meeting, No. 9 explains that Fry must stop the implosion of the violet dwarf and thwart the Dark One who is sure to be present. Though no one knows the Dark One's form, its mind cannot be read, allowing Fry to identify it. No. 9 gives Fry the Omega Device, which can temporarily disable the Dark One at close range.Bender frees the eco-feministas from prison in order to uphold his record for most crimes committed at once. Hermes, Zoidberg, Scruffy, and a repentant Farnsworth rescue them.At the ceremony, Fry cannot locate an unreadable mind; he concludes that he himself (having an unreadable mind) must be the Dark One. The eco-feministas disrupt the ceremony, but Fry convinces Leela to let him proceed. Fry activates the Omega Device, which creates a small dome around the two that appears to have no effect. Leela's leech falls to the ground and reveals itself as the final Dark One. The violet dwarf system forms a giant sperm and flies into the star, creating an Encyclopod embryo which quickly matures, taking the form of a giant manta ray-like creature. The Dark One kills Hutch, whose dying act is to pull Frida's necklace out of Fry's forehead, causing Fry to lose his telepathy. The Encyclopod kills the Dark One. No. 9 convinces the Encyclopod to preserve the Dark One's DNA, but Zoidberg eats the remains before it can. The Encyclopod preserves Hutch's DNA before leaving.Zapp attempts to apprehend the escaped prisoners, but the crew of the Planet Express ship and the Eco-feminists escape along with Kif. Fry and Leela profess their love for each other as the Nimbus chases the Planet Express ship toward a wormhole, which the Professor warns could take them trillions of light years away. Everyone agrees to go for it. Fry and Leela kiss as the ship enters the wormhole.Ending[edit]The ending refers to the uncertain future of the show. The makers were not sure if the show would return to TV, so if it did not, it is implied that the ship was in fact taken trillions of light years away. The show was picked up by Comedy Central, and it is revealed in the next episode "Rebirth" that the wormhole sent the ship directly back to Earth.
Output: Question: What type of creature does Leela save?, Answer: Martian muck leech