In the darkest corners of the internet lurks a support group so dangerous and twisted, the average person would never want to find it—or join it. But when the investigation into the death of Cyra Griffin's sister hits a standstill, Cyra must take matters into her own hands. The police are unhelpful, revealing nothing except for the hint that Mira's death might be the work of a serial killer. Using dubiously obtained insider information, Cyra infiltrates a serial killer support group that meets in New York City in an effort to unearth the truth about her sister’s death. But the dangerous men in the group aren't the only obstacle in finding her sister's killer. The longer Cyra stays in the group, the looser her grip becomes on her own morality. As the stakes get higher and her investigation gets more complicated, Cyra must decide between her thirst for revenge and her humanity.