A crime wave is sweeping Boston and police resources are stretched thin. The murder of a single mother is on the brink of becoming just another number in a wave of unsolved homicides. As the case goes cold for years, a toddler is left without his mom and an immigrant family faces an overwhelming justice system they can barely comprehend. Then, the nation’s top cold case duo attempts to catch her killer. They develop a technique that would change investigative procedure forever hoping to secure justice for a mother gone too soon.