The teenage crew of "Galahad," a space ship launched to find a home in a distant solar system for survivors on a virus-riddled Earth, are shaken by their encounter with the alien Cassini, but Triana and her Council are determined to continue the mission, even though they face increasing hostility from a faction led by the charismatic Merit Simms.

When the tail of the comet Bhaktul flicks through the Earth's atmosphere, deadly particles are left in its wake. Suddenly, mankind is confronted with a virus that devastates the adult population. Only those under the age of eighteen seem to be immune. A renowned scientist proposes a bold plan: to create a ship that will carry a crew of 251 teenagers to a home in a distant solar system. Two years later, the Galahad and its crew[none over the age of...

One year into their mission, as the teenaged crew of the Galahad is faced with waves of radiation that threaten the survival of their ship, Council leader Triana disappears and the crew must decide how to deal with assaults from both the outside and within their ranks.