Fry can't remember why he's covered with horrible burns. Professor Farnsworth explains: it all began a few days ago, while they were on the run from Zapp Brannigan. The wormhole they plunged through took them straight back to Earth. It turns out it was the Panama Wormhole, a major shipping route. Zapp's ship damaged the Planet Express, so the Professor activated the "safety spheres," which protected their heads (the Professor's was full-body). They crashed, and Zapp's ship crashed into their wreckage. The Professor was saved... as were all their heads. Their bodies ⎯ except for Fry's, apparently ⎯ have been reduced to skeletons. The Professor dips the bodies into a vat of adult stem cells, which regenerate everyone's bodies... even Bender's. Bender is low on power, so the Professor re-powers him with a Doomsday Device. Unfortunately it generates way too much power, so Bender must keep partying to keep from overloading and exploding. Also, Leela is in a coma, and the Professor says it's irreversible.
Fry is inconsolable, and everything reminds him of Leela. To try to take his mind off of her, he builds himself a robot girlfriend... that looks like Leela. Hermes shows them the security system that tapes every room, including the bathroom. The computer uses the tapes to extract a personality profile for Leela. This is downloaded into the Leela robot, which becomes a perfect duplicate of Leela, down to all her memories and emotions. Nibbler can tell it's not the real Leela, and attacks her, tearing off some of her skin to reveal to her that she's a robot. She freaks out. Fry apologizes; all he knows is that he loves her. That night, at a disco, Bender parties hard while Leela agonizes. Are her feelings real, or just artificial? She's got to figure this out. Until then, she and Fry are just friends.
The Professor makes one more attempt to revive the real Leela, with a machine that batters her body while shouting "WAKE UP!" It doesn't work. Leela's declared legally dead. Her body is taken to the Cyclophage preserve, where ⎯ per her living will ⎯ her body will be fed to the Cyclophage, which only eats cyclopes. The beast approaches as Bender continues to party through the funeral. His obnoxious partying finally wakes Leela. Celebrations are short-lived as Leela sees Fry kissing the robot Leela... and the monster is upon them. They flee. Both Leelas fight over who will pilot the ship. Back on Earth, both Leelas have a hard time dealing with their situation, leaving Fry alone. That night Fry tells Bender that if he loved robot Leela, it's only because there was so much of the real Leela in her. He thought Leela loved him, but he was wrong again. The real Leela is there, however, and overhears him. She tells him that he's right; she does love him. She's realized that if she lost him, she also couldn't stand it, and would also probably build a robot double of him. So long as robo-Leela isn't a jealous type like her, everything will be all right. Right on cue, robo-Leela arrives, threatening to kill the real Leela for moving in on Fry. They fight. Amy gives Fry a laser gun, but which one is the real Leela? "Kill her, she's the robot!" cries one. "No, kill her – she's the human!" cries the other. Fry's still confused. If they're going to be like that, he's not shooting anyone. He slams the gun down on the table... and shoots himself in the chest, blasting a hole right through himself... and discovers that he's also a robot! The Professor explains what really happened the day the ship crashed: just before impact, Fry shielded Leela with his body, saving Leela and leaving only a bit of his own hair and ash. The Professor put his remains in the stem cells, but he just bubbled away into the cellular stew without being reborn. Inconsolable, Leela made a robot Fry, but she overstuffed him with copper wadding. The static discharge when they kissed killed Leela, and shorted out both of their short-term memories. Leela can't believe she'll never see that particular Fry again... and right on cue, the vat discharges the original Fry, fully regenerated. It just took a while because so little of him was left. Robot Fry and Robot Leela declare their love for each other. They ditch their "meat jackets," and leave as robots. The real Leela's feelings are still a bit confused. Fry says he's waited for her for a thousand years... he can wait a little longer. Bender, disgusted with the mushy talk, decides to stop partying and kill them all when he explodes. Suddenly, the Cyclophage arrives. It goes for Leela... but as Bender shakes to pieces, he loses an eye, becoming a Cyclops. The beast eats him, containing the explosion. It kills the Cyclophage. Bender's okay, and the excess Doomsday energy has been blown out. Bender's cured. He never has to party again… time to party!