A crane collapses at a construction site and kills the son-in-law of wealthy real estate developer, Frank Linden. Nagel and Antonio, with the help of and CFD Chief Boden discover that the collapse wasn't actually an accident. The team digs into Linden, who has made many enemies, more dangerous friends, and is accustomed to using his money to get his way.

After a man is shot multiple times and left for dead, and a kilo of diluted heroin is found in his car, Antonio discovers other similar cases where murder victims were found with the same type of adulterated drugs. Ultimately, the narcotics detectives involved in the case-one a decorated hero-appear to be the common thread. Meanwhile, Stone is hesitant to let Nagel be involved in the case, as she has a close connection to the victim.

When an anti-environmentalist Alderman is killed during a vicious hit-and-run, Antonio and Nagel go all out to track down the driver. But instead of this being an organized hit to save the environment, it turns out the driver is a frantic mother desperate to save her kidnapped daughter. When Valdez discovers the mother was victim of a scam, the legal question becomes complicated: who is responsible for the Alderman's death? The mother trying to save her daughter? Or the perpetrators of the scam?

After an innocent girl is killed in a gang-related shooting that was instigated on social media, Stone's obsession for justice endangers the family of a cooperating witness. To salvage his crumbling case, Stone must go head-to-head in the courtroom against both the social media providers who inadvertently fueled the gang war and a cocky young man who may have pulled the trigger.

When Abigail Chapman returns from Spain after being acquitted for murdering her boyfriend while studying abroad, she finds herself the prime suspect in another murder case involving a young college student. During the trial of the real killer, the Second Amendment is put to the test.

When a female juror on Stone's case against a gangbanger winds up dead, the team believes she was murdered because of her guilty vote. They later learn that she committed suicide - driven to it by the cyber harassment of her former boyfriend. Stone goes after him for murder.

When a pregnant woman is found murdered and her baby cut out of her, the State's Attorney's Investigators race to find the baby and the killer. The case is complicated when it's revealed that the killer's DNA matches that of her father: a convicted serial killer already in prison. Both killers then attempt to use the DNA evidence as their ticket to freedom.

30 miles outside of Chicago, the cancer riddled body of Chicago PD Officer Tim Cody is found dead in a bathtub. When Antonio and Nagel arrive on scene they quickly determine his death was murder.