When the skull of 11-year-old Alan Watson is found in a field, Quinn and Velazquez take the case of a murder that took place almost a decade before.

Mother Shaquilla Weatherspoon is found murdered with her belongings scattered around her. To the trained eye, it looks like the killer staged the crime scene. Knowing that someone wanted it to look like a robbery, the detectives investigate those closest to Shaquilla to find the truth.

21-year-old new mother, Sparkle Rai, is found by her boyfriend strangled in their apartment. He instantly becomes the only suspect, but he swears he didn't do it. Quinn and Velazquez investigate and uncover a surprising new suspect from Sparkle's past.

Detectives are sent to an apartment complex to investigate when 38-year-old Cassandra Bryant is found nude and barely clinging to life. She dies in the ambulance before she can identify her attacker, leaving it up to Quinn and Velazquez.

When Quinn and Vince investigate the shooting of Antwan Curry, they find a trail of blood leading away from the murder scene, meaning that someone else was hurt and fled. They set out to find this person, but is it another victim, or the killer?

After working together a few years, Quinn and Velazquez are chosen to take on the case of Apriel Allen, a woman who was murdered in her apartment two years prior. The detectives start over with a clean slate and hope to bring some peace to the family and friends of Allen.

When immigrant Mamadou Berry is horrifically murdered, Quinn and Velazquez set out to find his killer. The yearlong investigation pits the detectives against the International Robbin Crew, a ruthless Atlanta gang that doesnt hesitate to use deadly force on their targets.

The detectives take the case of a homeless man who was shot and killed thinking it will be a simple case. However, after reports come back matching the murder scene to other ongoing murder cases, Quinn and Velazquez realize they're after a serial killer.