Environmental scientist Constance Roy is one of forty-nine refugees rescued from Earth's destruction and transported to the ark spaceship Orb by an automaton race called the Curators. Twelve months have passed since their rescue. But now, with the ship's orbit decaying, the refugees seem doomed to crash into Jupiter's fiery belly. In a parallel universe on present-day Earth, another version of Constance seeks answers to the questions that have haunted her since childhood: How and why did her mother die? The head of a mysterious corporation housed at NASA's Wallops Flight Facility can give her the answers, but not without a price. Two timestreams collide when the Constance on Earth discovers that Nicolas, her son, has the ability to save the Orb and its inhabitants. Now she must battle treacherous Curators wishing to destroy Nicolas, while on the Orb, another Constance must fight to save the ship from Jupiter's fatal pull. Only together can they save their son - and future generations of humankind.