This happened just before the Summer Tide, at a time when the twin planets Opal and Tecton were in orbits closest to their sun, subject (especially Tecton) to enormous tidal forces. This was to be the strongest Summer Tide ever to occur, creating something that only happened once every 350,000 years. Access to the unstable Quake was technically prohibited, but some very persistent travelers were determined to get there. Professor Dari Lang, who has been studying artifacts left behind by long-vanished aliens called the Builders, suggests that she might be able to find the Builders herself. Louis Nenda and the Cecropian Atvar H'sial had their own interests in Quake, and they were willing to do anything to get there. And Councilor Julius Graves was hunting the killers and was determined to find them even on Quake. Planetary Administrators Hans Rebke and Max Perry had no choice but to travel to Quake, risking their own lives to protect others, and perhaps discover the secret of Summertide and the Builders...