President Nixon and Zapp Brannigan enlist the Professor's help to destroy a Death Sphere, named V-GINY, headed towards Earth. Zapp and Leela pilot the Professor's invisible stealth fighter inside the V-GINY, but they are attacked and forced to crash down on an uninhabited paradise planet. Leela finds herself trapped under a fallen tree, forcing her to depend on Zapp for her survival. Soon Zapp and Leela begin surviving naked, using leaves to cover their privates, and the pair start to work through their past differences, particularly when the Earth's destruction at the hands of the Death Sphere forces Leela to ponder whether this planet is their own Garden of Eden, and whether she and Zapp are now humanity's Adam and Eve. Meanwhile, the crew find out the V-GINY only "censors indecent planets", which prompts them to convince the V-GINY that there's still purity in their world. The crew goes to the last unspoiled island on Earth after failing to convince the people of the world to repent. Shortly afterwards Leela discovers Zapp has been misleading her, and the crew stumble upon Leela and Zapp, explaining they're still on Earth. This enrages Leela even further and just as she's kicking Zapp's ass, they are approached by the V-GINY. The sphere proclaims that it's convinced there's still hope that this world might be redeemed, after watching Adam and Eve's antics, referring to Leela and Zapp. However, it orders them to consummate their union immediately. Failing to obey will lead to the planet's destruction. Leela weighs out her options and regards this as "taking one for the team". The V-GINY flying away pleased from Earth, and Fry screaming in agony due to his request for censoring the consummation being denied by the V-GINY. The episode ends with Zapp & Leela having sex.
Fry objects to the idea of Leela going on the mission to sabotage V-GINY, even before he knows that Zapp will accompany her. After he adjusts to the idea, he gives her a care package to take with her. It seems that his maturity level is still improving, something Leela surely appreciates, and she shows it with some tender words and even a kiss. This is a stability in their relationship that we haven't seen before.
Still, Fry is Fry: not ten seconds after he worries out loud about Leela's delayed return, he eagerly accepts Amy's offer of end-of-the-world sex. Sadly, when Zapp treats her better than dirt for more than ten seconds, Leela forgets all about Fry and is suddenly ready to bear Zapp's children. When she finally puts on the brakes with Zapp, it's not because of Fry at all, but because she starts to suspect Zapp of scamming her.
Fry discovers Leela and Zapp naked. He is happy to see Leela beating Zapp, but he shows no sign of jealousy, even when they have sex right in front of him. It's difficult to tell where Fry and Leela will go from here.