In 1963, the U.S. government launched a covert space mission sending hundreds of men, women and children on a century-long voyage aboard the starship Ascension to populate a new world. Nearly 50 years into the journey, as they approach the point of no return, a mysterious murder of a young woman causes the ship’s population to question the true nature of their mission.

When Natalie’s sister Grace becomes the prime suspect in her roommate Molly’s murder and popular target for the press and in social media, Natalie leaves her life in Boston and heads to London to defend her. With the help of an ethically questionable ex-pat lawyer Stan Gutterie, Natalie starts to question how innocent her sister may really be as more ugly truths start to come out.