In April 1994, Hutu extremists—known as the Interahamwe, or those that work together —assassinated Rwanda's president, and then embarked on a campaign of ruthless genocide against the minority Tutsi populations. Elijah Mutabazi, a sergeant in the Rwandan army, finds his younger sister dead on her apartment floor, having been gang-raped and slaughtered by teenage killers recruited by the Hutu-led Interahamwe. Over the ensuing months, Elijah spends his every waking hour caring for his grievously injured father, and protecting their village, Imaniku, from attack.

Upon returning to active military duty, Elijah learns that the international community, including the United Nations, had not come to aid those who had miraculously survived the genocide, but rather to ensure safe passage for the Interahamwe overlords. Elijah, unhinged by this revelation, deserts his army post and enters a world of reckless abandon via heroin, psychedelics, and grain alcohol, existing in a delusional state until a stint in a Burundian prison compels his sobriety.

Once a free man and reunited with his father and older brother, Cedric, Elijah's singular mission becomes one of vengeance against an active Interahamwe cell and its maniacal leader, Callixte Mbarushimana, who once served as a captain in the Rwandan Army and had been Elijah's mentor and commander.

Cedric, who years earlier had moved to the United States as an exchange student and had been spared the horrors of his country's genocide, had returned to his homeland with a group of medical volunteers to bring desperately needed surgical care to the children of Rwanda. Elijah, surrounded by healers for the first time, comes face-to-face with his past—and with the choice of being either an angel of death or an angel of mercy. That decision, one that would determine the course of his life, comes while staring his mortal enemy in the eye.