Emma Watson, a research physician, has been training for the mission of a lifetime: to study living organisms in the microgravity of space. But the true and lethal nature of the experiment has not been revealed to NASA, and once aboard the space station, things start to go wrong.

A culture of single-celled Archaeons, gathered from the deep sea, begins to rapidly multiply and infect the crew - with deadly and agonizing results. As her estranged husband and the ground crew at NASA work against the clock to launch a rescue, Emma struggles to contain the lethal microbe.

With the contagion threatening Earth's population, there are those who would leave the astronauts stranded in orbit, quarantined aboard the station. Emma must race against time to prevent a catastrophe.