Birmingham-based police officer DI Rachita Ray takes on a case that forces her to face a lifelong personal conflict.

总督察Roz Huntley刚刚侦破一起连环谋杀案，成功抓获一名连环凶手。然而法医官Tim Ifield却找到反腐小组AC-12，提出Roz在侦破过程中刻意忽略了对嫌疑人有利的证据，这起案件可能是一起冤案。于是AC-12的成员们展开了调查……