All developed societies of the Galaxy, to one degree or another, owe their development to the legacy of the Protheans, an ancient race that disappeared fifty thousand years ago. After a bunker containing some Prothean technology was found on Mars in 2148, humanity is rapidly gaining its place in cosmic society. And on the very edge of developed outer space, war hero and Alliance ship commander David Anderson is conducting an investigation into the death of a top-secret scientific base that was subjected to a terrorist attack. He is surrounded by smoking ruins, bodies of the dead and endless questions. Who attacked this object and for what purpose? And where is Kali Sanders, the young employee who mysteriously disappeared from the base hours before the attack? All the evidence points to Sanders as the main suspect, but meeting her raises even more questions for Anderson and provides no answers. The lieutenant fulfills his duty to humanity, paired with a partner he cannot trust, pursued by an assassin from whom he cannot escape, in the shadow of an ominous secret of an unknown world that he cannot tell anyone about... At least, that's what his enemy believes.