Just as Voight's crew get their hands on drugs kingpin, his cartel hit back by kidnapping Dawson's young son.

Sergeant Hank Voight and his team of officers find themselves in a race against time as they try to locate the kidnapper who has taken the son of one of their own, detective Antonio Dawson.

The kidnapping of Dawson's son continues to have ramifications for the team, although the boy is now safe. Voight manages to alienate his own son when his preoccupation with the case prevents him from meeting him upon his release from prison.

The team investigate the links between a crime lord and a deranged artist who may have been using his skills to create something less than legal.

After a balloon filled with cocaine bursts in the stomach of a student drug mule, the team frantically search for her three missing friends who have also been used to transport drugs and have been kidnapped on their return to Chicago.

The team call in help from New York's special victims unit when a serial rapist from the Big Apple starts to make a mark in the Windy City.