A nun has been murdered, a community shattered and everyone's faith in humanity is put to the test. The case pushes the team to their limits, as community outrage begins to rise. Yolanda finds herself questioning her path in life as her inner demons come calling, threatening to reveal a dark secret. Jimmy is haunted by his memories of war. Darius has his loyalties tested as Internal Affairs intensifies their pressure.

After the success of their last several cases, the reputation of the SIU is growing and they have earned the attention of New York Cities top officials including high ranking members of the United State government. When a former Russian diplomate ends up dead the SIU team is called in for a particular reason. Suddenly, the team finds themselves being pawns in an international conspiracy involving Russian money laundering, CIA spooks and former KGB hitmen. Yolanda is back, but a rift has formed between her and Jimmy as he attempts to ostracize her during the case. Tarik questions Jimmy's violent methods. Darius and Internal Affairs meet in secret.