When Fry eats an egg-salad sandwich from a vending machine at a gas station, he begins to have strange side-effects -- he becomes stronger and smarter. Professor Farnsworth makes a diagnosis and concludes that Fry had ingested "intelligent worms" that have set up shop in his body. Because these worms are so smart, the regular means of flushing them out will not work. The Planet Express crew makes miniature robotic versions of themselves and enter Fry's body to fight off the intruders. Meanwhile Leela is left to divert Fry's attention, but finds herself more and more attracted to the new man Fry has become. Leela ends up loving Fry, or at least what he has become. In the end Fry makes the worms leave, and Leela leaves him, because he turns back into the old Fry.