The crew of the Antares begins its mission, embarking on a six-year journey to explore Venus and the other planets in the solar system.

Crew members learn to adjust to life aboard the ship and face a life-threatening crisis.

Personal and professional relationships intensify, both aboard ship and on the ground, as the unseen power behind the mission begins to cause psychological and cellular transformations in the astronauts.

The crew faces its first major crisis when a series of system failures plunges everything into chaos, as power, heat and gravity-control are lost.

The ship crosses a critical boundary, at which point returning home is no longer an option, and each member of the crew must come to terms with that fact.

Some crew members struggle with guilt; a serious accident puts a crew member's life in danger.