It’s a race against time as Darius must accelerate his plan to stop the asteroid before the Pentagon shuts him down. Also, Grace has to make difficult decisions that could have life or death consequences for millions of people, and Liam and Jillian reunite under surprising circumstances.

Grace narrowly escapes a deadly assassin and Darius and Liam forge unlikely alliances.

Darius and Grace must forge an emotional détente to get international cooperation. Liam meets a new scientist who has a mysterious past.

Darius, Grace and Harris uncover the darkest secret yet, and Liam reconnects with Jillian.