Limited Collectors' Edition #55 (1978)

The Millennium Massacre, Superboy And The Legion Of Super-Heroes
Superboy travels to the future to attend the wedding of Lightning Lad and Saturn Girl. When he arrives, he finds a future he has never seen before, with everyone highly militarized and a state of constant warfare amont the planets. The other Legionnaires do not seem to see anything wrong, and their history says it all started in 1978 when there was a nuclear war. The constant warfare and hostilities have spread throughout the stars as humanity has spread. After the wedding ceremony, before the Legion can meet to figure out why Superboy remembers things differently, the newlyweds are kidnapped from the skies over Metropolis by the Lunarites. The team splits, part remaining behind to guard the headquarters, some heading for the Moon to rescue Garth and Imra, and the rest following Superboy's hunch to the past to investigate things there. The Lunar team successfully finds and rescues Lightning Lad and Saturn Girl, and the time travelers discover that things are being manipulated and time is being changed. They discover that the person behind this is the Time Trapper, but he defeats them and escapes. The two teams meet back at the Legion HQ, where they come together and take everyone to the end of time, to finally confront the Time Trapper.
Release Date: 1978