In San Diego on March 26, 1997, the bodies were found of 39 similarly dressed men and women who took their own lives in a mass suicide. Led by Marshall Applewhite, the Heaven's Gate cult believed that a flying saucer was traveling behind the Hale-Bopp comet. They chose to leave their physical bodies behind to find redemption in an extraterrestrial “Kingdom of Heaven.” The sect also left behind apocalyptic messages in their Rancho Santa Fe mansion and on home pages on the World Wide Web. This paper looks at online material produced by the cult and the media coverage of their tragic end, it explores the background of the cult and the science fiction and millennial influences on their beliefs, and it considers the group's connection with cyberculture and some of the questions raised by their mass suicide, which perhaps, as David Potz said in Slate, “promises to be the first great Internet mystery” [(Potz, March 28, 1997)].