 The Simpsons are in their backyard having a barbecue when they are abducted by extraterrestrial life forms ( specifically Kang and Kodos ) . The aliens explain that they are taking the Simpsons to their home planet on Rigel IV , " a world of infinite delights , " for a ' feast ' . En route they present the family with enormous amounts of food and watch eagerly as they gorge themselves , then check their weights , being particularly delighted at Homer 's mass . Suspicious of the alien 's intentions , Lisa sneaks into the kitchen and finds a book titled How To Cook Humans . She takes the book and shows it to the aliens , who explain to her that part of the title was obscured by space dust , which they then blow away to reveal the title How To Cook For Humans . Lisa , skeptical at this , blows off more space dust , revealing the title to be How To Cook Forty Humans . The aliens blow off the last of the space dust , finally revealing the real title How To Cook For Forty Humans . Enraged at Lisa 's mistrust , they return the Simpsons to Earth , explaining that Lisa ruined the family 's chance at paradise on the aliens ' home planet . Homer and Bart agree with the aliens , but Marge tries to explain to them that Lisa was just concerned for their family and didn 't know better . Even she agrees that Lisa sometimes needs to tone down her attitude and just ask . 
