experience from his family farm, Joel works as a farmer for the ship's crew of 500 and as a part-time musician. He regularly corresponds with Evelyn through the twins on board who maintain contact with Earth via telepathy with their siblings. Six "relativists" are essential to the voyage, controlling the ship's quantum ramjet drive with their minds. The drive has to run continuously; at relativistic speeds, it is nearly impossible to restart it, and then only for a short period after it has stopped. Each relativist can only stand the strain reliably for six hours a day. Five years into the voyage, one is killed and another mentally incapacitated, leaving no margin for error. The next year, the Sheffield learns through its telepaths that the Sun has gone nova, killing everyone in the solar system. A wavefront of deadly gamma radiation is expanding at lightspeed, threatening the colonies that are all that is left of humanity. The crew is only able to warn one colony in time; the rest are doomed. The Sun going nova is contrary to all astrophysical theories, and because over 90% of the sun's mass was converted into energy, it is suspected that an alien species caused the disaster. Unable to bear the catastrophe, one of the relativists commits suicide. Despite the other three's efforts, the quantum ramjet drive soon shuts down. The Sheffield will not be able to stop; it will coast by its intended destination at 97.6% of the speed of light. A vessel overtakes the ship, however; Jinny married a genius scientist who has developed a revolutionary faster-than-light drive. Only one experimental ship exists, capable of carrying ten people; aboard are several Conrads, including the domineering Richard, Jinny, her husband, and Evelyn, who has aged faster than Joel because of time dilation. She is now 19, and explains that she persuaded her grandfather into coming to get him. Conrad proposes an evacuation plan, shuttling people to their destination planet nine at a time. Joel eventually realizes that Conrad is lying; he only contacted the Sheffield to obtain needed supplies and has no intention of returning. The businessman wants to establish control of the colonies and cannot spare the time. Conrad is defeated and the faster-than-light engine is transferred to the Sheffield. Joel and Evelyn marry, then join the mission to warn the other colonies of the coming radiation wave. Joel decides to stay