Humanity has reached the stars, joining the vast intergalactic community of alien species. However, beyond the bounds of explored space lie the Reapers, a race of intelligent starships intent on "harvesting" the galaxy's organic species for dark purposes. The Illusive Man, leader of the pro-human black-operations group Cerberus, is one of the few who knows the truth about the Reapers. To ensure humanity's survival, he devises a desperate plan to uncover the enemy's strengths and weaknesses by studying someone who has implanted modified Reaper technology. He knows the perfect candidate for his gruesome experiments: former Cerberus operative Paul Grayson, who has freed his daughter from cabal control with the help of the Ascension project director, Kahlee Sanders. When Kahlee learns that Grayson is missing, she turns to the only person she can trust: Alliance war hero, Captain David Anderson. They set out together to find Cerberus's secret facility where Grayson is held. But they are not the only ones pursuing him. And time is running out.